U.S. patent application number 17/396463 was filed with the patent office on 2022-02-10 for wearable device with conductive traces and insulator.
The applicant listed for this patent is iRhythm Technologies, Inc.. Invention is credited to Jeffrey Joseph Abercrombie, II, James Kihyun Lee, Shena Hae Park, Thomas Burnell Reeve, III, Genaro Sebastian Sepulveda, Ryan James Wensley.
Application Number | 20220039721 17/396463 |
Document ID | / |
Family ID | 1000005814381 |
Filed Date | 2022-02-10 |
United States Patent
Application |
20220039721 |
Kind Code |
A1 |
Abercrombie, II; Jeffrey Joseph ;
et al. |
February 10, 2022 |
WEARABLE DEVICE WITH CONDUCTIVE TRACES AND INSULATOR
Abstract
The present disclosure relates to a wearable device that
includes a housing, battery terminal connector, conductive traces,
and an insulator for recording signals. The device may include a
housing enclosing a circuit board and a battery. The device may
include two conductive traces electrically connected to terminals
of the battery and an insulator separating the conductive traces.
The battery terminal connector can present both the conductive
traces to the outer surface for coupling to a circuit board. The
device can assess the physiological signals to infer a likelihood
of arrhythmia of a user.
Inventors: |
Abercrombie, II; Jeffrey
Joseph; (Oakland, CA) ; Sepulveda; Genaro
Sebastian; (Oakland, CA) ; Park; Shena Hae;
(San Francisco, CA) ; Wensley; Ryan James; (San
Francisco, CA) ; Lee; James Kihyun; (San Francisco,
CA) ; Reeve, III; Thomas Burnell; (San Francisco,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
iRhythm Technologies, Inc. |
San Francisco |
CA |
US |
|
|
Family ID: |
1000005814381 |
Appl. No.: |
17/396463 |
Filed: |
August 6, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
63062314 |
Aug 6, 2020 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 5/6833 20130101;
A61B 5/6843 20130101; A61B 5/257 20210101; H05K 1/147 20130101;
A61B 2562/166 20130101; H05K 5/0086 20130101; H05K 5/0217 20130101;
H05K 7/1427 20130101; A61B 5/282 20210101; A61B 2562/227 20130101;
A61B 5/325 20210101; A61B 2562/0215 20170801; A61B 2090/0807
20160201; A61B 2562/0217 20170801 |
International
Class: |
A61B 5/257 20060101
A61B005/257; H05K 7/14 20060101 H05K007/14; H05K 5/02 20060101
H05K005/02; H05K 5/00 20060101 H05K005/00; A61B 5/00 20060101
A61B005/00; A61B 5/325 20060101 A61B005/325 |
Claims
1. A wearable device for monitoring physiological signals in a
user, the device comprising: a housing enclosing a circuit board
and at least one battery, the battery comprising a first terminal
on a bottom side of the battery and a second terminal on a top side
of the battery; and a flexible wing extending from the housing
between a top housing and a bottom housing and configured to
conform to a surface of the user, the flexible wing having a bottom
surface and a top surface, wherein the housing comprises the top
housing coupled to the bottom housing; an electrode coupled to the
flexible wing, the electrode in electrical communication with the
circuit board and being configured to be positioned in conformal
contact with the surface of the user to detect the physiological
signals; and an adhesive layer coupled to the bottom surface of the
flexible wing for adhering the wearable device to the user; a
battery terminal connector, the battery terminal connector
comprising: a bottom portion configured to contact the bottom side
of the battery; a top portion configured to contact the top side of
the battery; and a connecting portion configured to extend from the
bottom portion to the top portion; wherein the battery terminal
connector comprises an inner surface extending over the bottom
portion, top portion, and connecting portion of the battery
terminal connector, the inner surface being configured to face
toward the battery, and an outer surface extending over the bottom
portion, top portion, and connecting portion of the battery
terminal connector, the outer surface being configured to face away
from the battery, wherein the battery terminal connector further
comprises: a first conductive trace disposed on the inner surface
of the bottom portion and on the outer surface of the top portion,
the first conductive trace being configured to electrically connect
to the first terminal of the battery; a second conductive trace
disposed on the inner surface of the top portion and on the outer
surface of the top portion, the second conductive trace being
configured to electrically connect to the second terminal of the
battery; and an insulator disposed on the inner and outer surfaces
of the top portion, the insulator separating the first conductive
trace from the second terminal of the battery and separating the
first conductive trace from the second conductive trace; and
wherein the battery terminal connector is configured to present
both the first and second conductive traces on the outer surface of
the top portion for electric coupling to the circuit board.
2. The wearable device of claim 1, wherein the insulator is not
disposed on the bottom portion of the battery terminal
connector.
3. The wearable device of claim 1, wherein the second conductive
trace is disposed on an outer surface of the insulator but extends
beyond an edge of the insulator on the top portion of the battery
terminal connector to form an extension configured to make
electrical contact with the second terminal.
4. The wearable device of claim 1, wherein the second conductive
trace is disposed on an inner surface and an outer surface of the
insulator and wherein the inner and outer portions of the second
conductive trace are electrically connected by vias extending
through the insulator and filled with conductive material.
5. The wearable device of claim 1, wherein the first and second
conductive traces of the battery terminal connector are arranged
substantially in a same horizontal plane as the contact region of
the trace layer for electric coupling to the circuit board.
6. The wearable device of claim 5, wherein the trace layer
comprises a central aperture in an area positioned within housing
and the first and second conductive traces of the battery terminal
connector are positioned within the central aperture such that the
contact region of the trace layer.
7. The wearable device of claim 5, wherein the circuit board is
positioned above the trace layer and wherein the circuit board is
electrically coupled to the contact region of the trace layer and
the first and second conductive traces of the battery terminal
connector by a spring contacts.
8. The wearable device of claim 7, wherein the circuit board is
spaced apart from the trace layer by a spring contact spacer
comprising holes allowing the spring contacts to extend through the
spring contact spacer, the spring contact spacer being configured
to maintain a substantially consistent separation distance between
the circuit board and the contact region of the trace layer as well
as between the circuit board and the first and second conductive
traces of the battery terminal connector.
9. The wearable device of claim 1, further comprising a spring
positioned beneath the bottom side of the battery, the spring being
configured to bias the first and second conductive traces of the
battery terminal connector into electrical contact with the circuit
board.
10. The wearable device of claim 9, wherein the spring is a wave
spring.
11. The wearable device of claim 1, wherein the housing further
comprises: a column extending downward from the top housing and a
post extending upward from the bottom housing, the post being
received in the column or the column being received in the post,
wherein the column and post are press-fit together and configured
to resist internal forces within the housing that promote
separating the top housing from the bottom housing.
12. The wearable device of claim 11, further comprising a spring
positioned between a bottom surface of the bottom housing and the
circuit board, the spring configured to subsume tolerance stack
within the housing.
13. The wearable device of claim 12, wherein the housing encloses a
battery and the spring is further configured to bias traces
electrically connected to the battery terminals and a trace
electrically coupled to the electrode into electrical contact with
the circuit board.
14. The wearable device of claim 13, wherein the electrical contact
is made via a plurality of spring contacts.
15. The wearable device of claim 12, wherein the spring is a wave
spring.
16. The wearable device of claim 12, further comprising a spacer
positioned between the circuit board and a battery, the spacer
being configured to maintain the battery at a constant separation
distance from the circuit board.
17. The wearable device of claim 11, further comprising foam
positioned between a bottom surface of the bottom housing and the
circuit board, the foam configured to subsume tolerance stack
within the housing.
18. A wearable device for monitoring physiological signals in a
user, the device comprising: a housing enclosing a circuit board
and at least one battery, the battery comprising a first terminal
on a bottom side of the battery and a second terminal on a top side
of the battery; and a battery terminal connector, the battery
terminal connector comprising: a bottom portion configured to
contact the bottom side of the battery; a top portion configured to
contact the top side of the battery; and a connecting portion
configured to extend from the bottom portion to the top portion;
wherein the battery terminal connector comprises an inner surface
extending over the bottom portion, top portion, and connecting
portion of the battery terminal connector, and an outer surface
extending over the bottom portion, top portion, and connecting
portion of the battery terminal connector, wherein the battery
terminal connector further comprises: a first conductive trace
disposed on the inner surface of the bottom portion and on the
outer surface of the top portion, the first conductive trace being
configured to electrically connect to the first terminal of the
battery; a second conductive trace disposed on the inner surface of
the top portion and on the outer surface of the top portion, the
second conductive trace being configured to electrically connect to
the second terminal of the battery; and an insulator disposed on
the inner and outer surfaces of the top portion, the insulator
separating the first conductive trace from the second terminal of
the battery and separating the first conductive trace from the
second conductive trace.
19. The wearable device of claim 18, wherein the insulator is not
disposed on the bottom portion of the battery terminal
connector.
20. The wearable device of claim 18, wherein the second conductive
trace is disposed on an outer surface of the insulator but extends
beyond an edge of the insulator on the top portion of the battery
terminal connector to form an extension configured to make
electrical contact with the second terminal.
21. The wearable device of claim 18, wherein the second conductive
trace is disposed on an inner surface and an outer surface of the
insulator and wherein the inner and outer portions of the second
conductive trace are electrically connected by vias extending
through the insulator and filled with conductive material.
22. The wearable device of claim 18, wherein the first and second
conductive traces of the battery terminal connector are arranged
substantially in a same horizontal plane as the contact region of
the trace layer for electric coupling to the circuit board.
23. The wearable device of claim 18, the device comprising: a
flexible wing extending from the housing between a top housing and
a bottom housing and configured to conform to a surface of the
user, the flexible wing having a bottom surface and a top surface,
wherein the housing comprises the top housing coupled to the bottom
housing; an electrode coupled to the flexible wing, the electrode
in electrical communication with the circuit board and being
configured to be positioned in conformal contact with the surface
of the user to detect the physiological signals; and an adhesive
layer coupled to the bottom surface of the flexible wing for
adhering the wearable device to the user.
24. An abrading device for preparing the skin of a user for
adhering a physiological monitoring device, the abrading device
comprising: a housing configured to allow a user to hold the
abrading device; an abrading surface positioned on a bottom side of
the housing, the abrading surface configured to abrade the user's
skin, wherein the abrading surface is configured to project below
the bottom side of the housing or retract within the housing; and a
compressible element coupling the abrading surface to the housing
and configured to bias the abrading surface downward such that
increasing downward pressure on the housing increases compression
of the compressible element and decreases the amount by which the
abrading surface projects below the bottom side of the housing.
25. The abrading device of claim 24, wherein the compressible
element is a spring.
26. The abrading device of claim 24, wherein the compressible
element is a foam element.
27. The abrading device of claim 26, wherein the foam element is an
open cell foam having an internal color and an external color, the
internal color being distinct from the external color, and wherein
the abrading device is calibrated such that exertion of an optimal
amount of pressure against the skin of the user compresses the open
cell foam to an extent such that the internal color is not visible
to the user.
28. The abrading device of claim 24, wherein the abrading device is
configured to be fully retracted into the housing upon exceeding a
limit of pressure desired to be applied between the abrading
surface and the user's skin.
29. The abrading device of claim 24, wherein the bottom side of the
housing is configured to contact the user's skin upon achieving an
optimal amount of pressure between the abrading surface and the
user's skin.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from provisional U.S. Pat.
App. No. 63/062,314, filed on Aug. 6, 2020, which is hereby
incorporated by reference in its entirety.
BACKGROUND
[0002] For purposes of this disclosure, certain aspects,
advantages, and novel features of various embodiments are described
herein. It is to be understood that not necessarily all such
advantages may be achieved in accordance with any particular
embodiment. Thus, various embodiments may be or carried out in a
manner that achieves one advantage or group of advantages as taught
herein without necessarily achieving other advantages as may be
taught or suggested herein.
FIELD OF THE INVENTION
[0003] Disclosed herein are materials, devices, methods, and
systems for monitoring physiological signals. For example, such
physiological signals may include heart signals, such as an
electrocardiogram signal.
DESCRIPTION OF THE RELATED ART
[0004] Abnormal heart rhythms, or arrhythmias, may cause various
types of symptoms, such as loss of-consciousness, palpitations,
dizziness, or even death. An arrhythmia that causes such symptoms
is often an indicator of significant underlying heart disease. It
is important to identify when such symptoms are due to an abnormal
heart rhythm, since treatment with various procedures, such as
pacemaker implantation or percutaneous catheter ablation, can
successfully ameliorate these problems and prevent significant
symptoms and death. For example, monitors, such as Holter monitors
and similar devices, are currently in use to monitor heart
rhythms.
BRIEF SUMMARY OF EMBODIMENTS
[0005] Embodiments described herein are directed to a physiological
monitoring device that may be worn continuously and comfortably by
a human or animal subject for at least one week or more and more
typically two to three weeks or more. In one embodiment, the device
is specifically designed to sense and record cardiac rhythm (for
example, electrocardiogram, ECG) data, although in various
alternative embodiments one or more additional physiological
parameters may be sensed and recorded. Such physiological
monitoring devices may include a number of features to facilitate
and/or enhance the patient experience and to make diagnosis of
cardiac arrhythmias more accurate and timely.
[0006] In some embodiments, a wearable device for monitoring
physiological signals in a mammal comprises: at least two flexible
wings extending laterally from a housing, wherein the flexible
wings comprise a first set of materials which enable the wings to
conform to a surface of the mammal and the housing comprises a
second set of materials; a printed circuit board assembly housed
within the housing, wherein the housing is configured to prevent
deformation of the printed circuit board in response to movement of
the mammal; at least two electrodes embedded within the flexible
wings, the electrodes configured to provide conformal contact with
the surface of the mammal and to detect the physiological signals
of the mammal; at least two electrode traces embedded within the
wings and mechanically decoupled from the housing, the electrode
traces configured to provide conformal contact with the surface of
the mammal and transmit electrical signals from the electrodes to
the printed circuit board assembly; and, at least one hinge portion
connecting the wings to the housing, the hinge portions configured
to flex freely at the area where it is joined to the housing.
[0007] In certain embodiments, each wing may comprise an adhesive.
In embodiments, the electrodes can be in the same plane as the
adhesive. In certain embodiments, each wing comprises at least one
rim, wherein the rim is thinner than an adjacent portion of each
wing. The housing may further comprise dimples or grooves
configured to allow for airflow between the housing and the surface
of the mammal. In certain embodiments, the rim is configured to
prevent the release of a portion of the wing from the surface of
the mammal. In some embodiments, a wearable device for monitoring
physiological systems may comprise a measuring instrument
configured to detect motion signals in at least one axis. This
measuring instrument may be an accelerometer that can be configured
to detect motion signals in three axes.
[0008] In embodiments, the motion signals can be collected in time
with the physiological signals. In certain embodiments, a motion
artifact is identified when the physiological signals and the
motion signals match. Further embodiments may call for an event
trigger coupled to the printed circuit board assembly. In some
embodiments, the event trigger input is supported by the housing or
floating on a shock absorber such as a spring or foam so as to
prevent mechanical stress on the printed circuit board when the
trigger is activated which, in turn, can reduce a source of
artifact in the recorded signal.
[0009] In some embodiments, the event trigger may be concave or
convex and larger than a human finger such that the event trigger
is easily located. In some embodiments the event trigger may be
convex within the concave area. In certain embodiments, the
electrode traces are configured to minimize signal distortion
during movement of the mammal. In particular embodiments, gaskets
may be used as a means for sealable attachment to the housing.
[0010] In certain embodiments, a method for monitoring
physiological signals in a mammal may comprise: attaching a
wearable device to the mammal, wherein the device comprises: at
least two electrodes configured to detect physiological signals
from the mammal, at least one measuring instrument configured to
detect secondary signals, and at least two electrode traces
connected to the electrodes and a housing; and, comparing the
physiological signals to the secondary signals to identify an
artifact.
[0011] In certain embodiments, identification of artifacts
comprises a comparison between the frequency spectrum of the
physiological signals and the frequency spectrum of the secondary
signals. In embodiments, the secondary signals comprise motion
signals that may be used to derive the activity and position of the
mammal. In certain embodiments, the secondary signals are collected
in three axes. In some embodiments, a tertiary signal may also be
collected. In certain embodiments, the secondary signals comprise
information about the connection between the wearable device and
the mammal. In some embodiments, the secondary signals may be used
to detect when the mammal is sleeping.
[0012] In some embodiments, a method of removing and replacing
portions of a modular physiological monitoring device may comprise:
applying the device described above to a mammal for a period of
time greater than 7 days and collecting physiological data; using
the device to detect a first set of physiological signals; removing
the device from the surface of the mammal; removing a first
component from the device; and, incorporating the first component
into a second physiological monitoring device, the second
physiological monitoring device configured to detect a second set
of physiological signals.
[0013] In some embodiments, the first component is electrically
connected to other device components without the use of a permanent
connection. In some embodiments, the device may further comprise
spring connections. In certain embodiments, the first component may
be preserved for a second use by a housing to prevent damage. In
particular embodiments, the first component is secured within a
device by a mechanism that is capable of re-securing a second
component once the first component is removed.
[0014] Certain embodiments may concern a system for inferring
cardiac rhythm information from time-series data of heartbeat
intervals, as obtained from either consumer wearable or medical
device products. A further aspect includes improvements to the
system to enable cardiac rhythm information to be inferred in a
more robust and/or timely manner through the use of additional
sources of data. This additional data may include summary
statistics or specific signal features derived from an ECG, user
activity time series data derived from an accelerometer,
information related to user state, or information related to the
day/time of the recording.
[0015] In certain embodiments, a system for selective transmission
of electrocardiographic signal data from a wearable medical sensor,
where QRS refers to the three fiducial points of an ECG recording
at the time of ventricle depolarization, may comprise:
[0016] a wearable medical sensor incorporating a QRS detector that
produces a real-time estimate of each R peak location in the
ECG;
[0017] transmission of an R-R interval time series together with an
onset time stamp from the sensor to a smartphone or
Internet-connected gateway device, according to a predefined
schedule;
[0018] transmission of the R-R interval time series and the onset
time stamp from the smartphone or internet-connected gateway device
to a server;
[0019] server-side algorithmic inference of the most probable
rhythms and their onset/offset times from the R-R interval time
series data;
[0020] filtering the list of inferred heart rhythms according to
specific filter criteria, such that only inferred rhythms matching
the given criteria are retained after filtering;
[0021] transmission of the onset/offset time for each rhythm
remaining after filtering, from the server to the smartphone or
internet-connected gateway device;
[0022] transmission of the onset/offset time for each rhythm
remaining after filtering, from the smartphone or
internet-connected gateway device to the wearable sensor;
[0023] transmission of the section of recorded ECG corresponding to
each onset-offset time pair from the sensor to the smartphone or
internet-connected gateway device;
[0024] transmission of the section of recorded ECG corresponding to
each onset-offset time pair from the smartphone or
internet-connected gateway device to the server;
[0025] The rhythm filter criteria may be specified by a physician
or other medical professional prior to the use of the wearable
sensor by a patient. In some embodiments, the rhythm filter
criteria are dynamic and can be updated during the use of the
system according to predefined rules. In some embodiments, these
predefined rules may describe an adjustment to the filter criteria
based on previous findings during use of the system. In some
embodiments, the onset and offset time for each inferred rhythm may
be adjusted such that the resulting duration for each rhythm is
less than a given maximum permissible duration. Computed confidence
measures may be an input to the rhythm filter criteria. In some
embodiments, the system comprises inferring cardiac rhythm
information from R-R interval time series data. In certain
embodiments, the cardiac rhythm inference system is implemented as
a cloud service accessible via an API.
[0026] In certain embodiments, the cardiac rhythm inference system
is provided through a software library that can be incorporated
into a standalone application. The R-R interval values may be
estimated from a photoplethysmography signal.
[0027] In certain embodiments of a method for inferring cardiac
rhythm information, the cardiac rhythm inference system computes a
confidence score for each type of cardiac rhythm, the method
comprising:
[0028] computing the frequency and duration of each cardiac rhythm
type inferred from the collection of R-R interval time series data
for the given user;
[0029] estimating a confidence statistic for each rhythm type based
on the inferred frequency and duration of the rhythm across the
collection of R-R interval time series for the given user;
[0030] evaluating if the confidence statistic for each inferred
rhythm exceeds a pre-determined threshold value;
[0031] providing rhythm information back to the calling software
only for those inferred rhythms for which the confidence statistic
exceeds the threshold value;
[0032] In certain embodiments, the cardiac rhythm inference system
accepts additional sources of data, comprising one or more of:
[0033] user activity time series data measured by an
accelerometer;
[0034] information on the specific day and time of each R-R
interval time series recording;
[0035] information on user age, gender, clinical indication for
monitoring, pre-existing medical conditions, medication
information, and medical history;
[0036] ECG signal features and summary statistics, such as the
mean, median, standard deviation or sum of the ECG signal sample
values within a given time period;
[0037] a confidence rating provided by the measurement device to
indicate the quality of heartbeat estimation, for example, for each
beat or for sequential time periods; and
[0038] intra-beat interval measurements.
[0039] In embodiments, a system for monitoring cardiac signal data,
comprises:
[0040] a wearable medical sensor, the wearable medical sensor
configured to detect cardiac signals from a mammal and estimate the
R-peak location within the cardiac signal;
[0041] wherein the wearable medical sensor is configured to
transmit an R-R interval time series and a time stamp to an
intermediary device, the intermediary device configured to further
transmit the R-R interval time series and time stamp to a
server;
[0042] wherein the server is configured to infer the most probable
rhythms and their onset/offset times from the R-R interval time
series and time stamp, the server configured to filter the most
probable rhythms according to a first criteria into a filtered data
set;
[0043] wherein the server is configured to transmit the filtered
data set back to the wearable sensor via the intermediary device;
and
[0044] wherein the sensor transmits the full resolution cardiac
signal to the server for a time period surrounding each of the
filtered events.
[0045] In certain embodiments, a system for monitoring cardiac
signal data comprises: [0046] a server configured to communicate
with a wearable sensor, the wearable sensor configured to detect
cardiac signals from a mammal and estimate the R peak location
within the cardiac signal; [0047] wherein the wearable sensor is
configured to transmit an R-R interval time series and a time stamp
to the server; [0048] wherein the server is configured to infer the
most probable rhythms and their onset/offset times from the R-R
interval time series and time stamp, the server configured to
filter the most probable rhythms according to a first criteria into
a filtered data set; and [0049] wherein the server is configured to
transmit a summary of the filtered data.
[0050] In particular embodiments, a server for monitoring cardiac
signal data, comprises: [0051] a portal configured to communicate
with a wearable sensor, the wearable sensor configured to detect
cardiac signals from a mammal and estimate the R peak location
within the cardiac signal, wherein the wearable sensor is
configured to transmit an R-R interval time series and a time stamp
to an intermediary device, the intermediary device configured to
further transmit the R-R interval time series and time stamp to a
server; [0052] a processor configured to infer the most probable
rhythms and their onset/offset times from the R-R interval time
series and time stamp, the processor configured to filter the most
probable rhythms according to a first criteria into a filtered data
set; and [0053] wherein the server is configured to transmit a
summary of the filtered data set.
[0054] In embodiments, a non-transitory storage medium having
computer-executable instructions stored thereon, the
computer-executable instructions readable by a computing system
comprising one or more computing devices, wherein the
computer-executable instructions are executable on the computing
system in order to cause the computing system to perform operations
comprises: receiving, by a computing system through a communication
link, physiological sensor data generated by a patient monitoring
device, the physiological sensor data associated with a first
patient; analyzing, by the computing system, the physiological
sensor data to determine whether one or more points in the
physiological data that are likely indicative of one or more
predetermined set of conditions; and after determining that at
least one of the one or more points in the physiological data is
likely indicative of at least one of the one or more predetermined
set of conditions, generating, by the computing system, an
electronic data package for transmission to the patient monitoring
device, the electronic data package including location data
regarding the at least one of the one or more points in the
physiological sensor data that are likely indicative of the at
least one of the one or more predetermined set of conditions.
[0055] In certain embodiments, the physiological sensor data may
comprise a sampling of interval data measured from the recorded
signal data, the sampling of interval data of a data size less than
the recorded signal data.
[0056] In particular embodiments, a system for monitoring
physiological signals in a mammal may comprise: a wearable adhesive
monitor configured to detect and record cardiac rhythm data from a
mammal, the wearable adhesive monitor configured to extract a
feature from the cardiac rhythm data; and wherein the wearable
adhesive monitor is configured to transmit the feature to a
processing device, the processing device configured to analyze the
feature, identify locations of interest, and transmit the locations
of interest back to the wearable adhesive monitor.
[0057] In certain embodiments, a system for assessing physiological
sensor data from a patient monitoring device comprises: a computer
processor and non-transitory computer-readable media combined with
the computer processor configured to provide a program that
includes a set of instructions stored on a first server, the set of
instructions being executable by the computer processor, and
further configured to execute a sensor data inference module of the
program; the sensor data inference module of the program storing
instructions to: receive physiological sensor data generated by a
patient monitoring device, the physiological sensor data associated
with a first patient; analyze the physiological sensor data to
determine whether one or more points in the physiological data that
are likely indicative of one or more predetermined set of
conditions; and after determining that at least one of the one or
more points in the physiological data is likely indicative of at
least one of the one or more predetermined set of conditions,
generating an electronic data package for transmission to the
patient monitoring device, the electronic data package including
location data regarding the at least one of the one or more points
in the physiological sensor data that are likely indicative of the
at least one of the one or more predetermined set of
conditions.
[0058] In certain embodiments, a computerized method may comprise:
accessing computer-executable instructions from at least one
computer-readable storage medium; and executing the
computer-executable instructions, thereby causing computer hardware
comprising at least one computer processor to perform operations
comprising: receiving, by a server computer through a communication
link, physiological sensor data generated by a patient monitoring
device, the physiological sensor data associated with a first
patient; analyzing, by the server computer, the physiological
sensor data to determine whether one or more points in the
physiological data that are likely indicative of one or more
predetermined set of conditions; and after determining that at
least one of the one or more points in the physiological data is
likely indicative of at least one of the one or more predetermined
set of conditions, generating, by the server computer, an
electronic data package for transmission to the patient monitoring
device, the electronic data package including location data
regarding the at least one of the one or more points in the
physiological sensor data that are likely indicative of the at
least one of the one or more predetermined set of conditions.
[0059] These and other aspects and embodiments of the invention are
described in greater detail below, with reference to the drawing
figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0060] FIGS. 1A and 1B are perspective and exploded profile views,
respectively, of a physiological monitoring device, according to
one embodiment.
[0061] FIGS. 2A and 2B are top perspective and bottom perspective
views, respectively, of a printed circuit board assembly of the
physiological monitoring device, according to one embodiment.
[0062] FIGS. 3A, 3B, 3C, 3D, and 3E are perspective and exploded
views of a flexible body and gasket of the physiological monitoring
device, according to one embodiment.
[0063] FIG. 4 is an exploded view of a housing of the physiological
monitoring device; according to one embodiment.
[0064] FIGS. 5A and 5B provide a perspective view of a battery
holder of the physiological monitoring device, according to one
embodiment.
[0065] FIGS. 6A and 6B are cross sectional views of the
physiological monitoring device, according to one embodiment.
[0066] FIG. 7 is an exploded view of the physiological monitoring
device including a number of optional items, according to one
embodiment.
[0067] FIGS. 8A and 8B are perspective views of two people wearing
the physiological monitoring device, illustrating how the device
bends to conform to body movement and position, according to one
embodiment.
[0068] FIGS. 9A, 9B, 9C, 9D, 9E, and 9F illustrate various steps
for applying the physiological monitor to a patient's body,
according to one embodiment.
[0069] FIGS. 10A-10C schematically illustrate alternative examples
of a trace layer. FIG. 10A illustrates a first example of a trace
layer and FIG. 10B depicts a close-up of the inset A of FIG. 10A.
FIG. 10C illustrates another example of a trace layer.
[0070] FIGS. 11A-11I schematically depict examples of a battery
terminal connector. FIG. 11A depicts an inner surface of a battery
terminal connector configured to contact the battery terminals and
FIG. 11B depicts an outer surface of the battery terminal connector
opposite the surface depicted in FIG. 11A. FIG. 11C depicts an
inner surface of another example of a battery terminal connector
configured to contact the battery terminals and FIG. 11D depicts an
outer surface of the battery terminal connector opposite the
surface depicted in FIG. 11C. FIG. 11E illustrates a side view of a
battery to which a battery terminal connector has been coupled.
FIGS. 11F and 11G depict an inner surface of another example of a
battery terminal connector configured to contact the battery
terminals. FIGS. 11H and 11I depict an outer surface of the battery
terminal connector opposite the surface depicted in FIG. 11C.
[0071] FIGS. 12A-12G illustrate multi-perspective views of another
example of an upper housing. FIG. 12A depicts a partially exploded
view of the upper housing. FIG. 12B shows a perspective view of a
flexible upper frame. FIG. 12C shows a side view of the flexible
upper frame. FIG. 12D shows a top view of the flexible upper frame.
FIG. 12E depicts a perspective view of an inner surface of the
upper housing. FIG. 12F depicts a side view of the upper and lower
housing. FIG. 12G depicts a side view of a ridge configured for
sealing the top and bottom portions of the housing.
[0072] FIGS. 13A-13B illustrate multi-perspective views of another
example of a lower housing. FIG. 13A depicts a perspective view of
the lower housing and FIG. 13B depicts a side view of the lower
housing.
[0073] FIGS. 14A-14B illustrate orthogonal side views of an example
of a wave spring.
[0074] FIGS. 15A-15I illustrate multiple views of another example
of a physiological monitoring device. FIG. 15A depicts a
perspective view of the physiological monitoring device. FIG. 15B
depicts an exploded view of the physiological monitoring device.
FIG. 15C depicts a side view of the housing in which the upper
housing has been removed. FIG. 15D depicts a side view of the
housing as shown in FIG. 15C with flexible upper frame additionally
being removed. FIG. 15E depicts a side view of the housing as shown
in FIG. 15D with the lower housing additionally being removed. FIG.
15F depicts a side view of the housing as shown in FIG. 15E with
the battery and spring additionally being removed. FIG. 15G depicts
a sectional view of the housing as shown in FIG. 15F with the
section taken between the circuit board 120 and the spring contact
spacer 632. FIG. 15H depicts a sectional view of the housing as
shown in FIG. 15G with the spring contact spacer additionally being
removed. FIG. 15I depicts a side view of the housing as shown in
FIG. 15H additionally including the circuit board.
[0075] FIGS. 16A-16D illustrate multiple views of embodiments of a
physiological monitoring device. FIG. 16A shows a top perspective
view, FIG. 16B shows a bottom view, FIG. 16C shows a top
perspective view including liners, FIG. 16D shows a bottom view
including liners.
[0076] FIGS. 17A and 17B schematically illustrate cross-sectional
views of two examples of an abrader. FIG. 17A depicts an abrader
comprising a compressible spring. FIG. 17B depicts an abrader
comprising a compressible foam.
[0077] FIG. 18 illustrates a schematic diagram of an embodiment of
a cardiac rhythm inference service.
[0078] FIG. 19 is a schematic diagram of an embodiment of a system
for extracting and transmitting data features from a physiological
monitor.
DETAILED DESCRIPTION OF EMBODIMENTS
[0079] The following description is directed to a number of various
embodiments. The described embodiments, however, may be implemented
and/or varied in many different ways. For example, the described
embodiments may be implemented in any suitable device, apparatus,
or system to monitor any of a number of physiological parameters.
For example, the following discussion focuses primarily on
long-term, patch-based cardiac rhythm monitoring devices. In one
alternative embodiment, a physiological monitoring device may be
used, for example, for pulse oximetry and diagnosis of obstructive
sleep apnea. The method of using a physiological monitoring device
may also vary. In some cases, a device may be worn for one week or
less, while in other cases, a device may be worn for at least seven
days and/or for more than seven days, for example between fourteen
days and twenty-one days or even longer.
[0080] Many other alternative embodiments and applications of the
described technology are possible. Thus, the following description
is provided for exemplary purposes only. Throughout the
specification, reference may be made to the term "conformal." It
will be understood by one of skill in the art that the term
"conformal" as used herein refers to a relationship between
surfaces or structures where a first surface or structure adapts to
the contours of a second surface or structure.
[0081] Since abnormal heart rhythms or arrhythmias can often be due
to other, less serious causes, a key challenge is to determine when
any of these symptoms are due to an arrhythmia. Oftentimes,
arrhythmias occur infrequently and/or episodically, making rapid
and reliable diagnosis difficult. As mentioned above, currently,
cardiac rhythm monitoring is primarily accomplished through the use
of devices, such as Holter monitors, that use short-duration (less
than 1 day) electrodes affixed to the chest. Wires connect the
electrodes to a recording device, usually worn on a belt. The
electrodes need daily changing and the wires are cumbersome. The
devices also have limited memory and recording time. Wearing the
device interferes with patient movement and often precludes
performing certain activities while being monitored, such as
bathing.
[0082] Further, Holter monitors are capital equipment with limited
availability, a situation that often leads to supply constraints
and corresponding testing delays. These limitations severely hinder
the diagnostic usefulness of the device, the compliance of patients
using the device, and the likelihood of capturing all important
information. Lack of compliance and the shortcomings of the devices
often lead to the need for additional devices, follow-on
monitoring, or other tests to make a correct diagnosis.
[0083] Current methods to correlate symptoms with the occurrence of
arrhythmias, including the use of cardiac rhythm monitoring
devices, such as Holter monitors and cardiac event recorders, are
often not sufficient to allow an accurate diagnosis to be made. In
fact, Holter monitors have been shown to not lead to a diagnosis up
to 90% of the time ("Assessment of the Diagnostic Value of 24-Hour
Ambulatory Electrocardiographic Monitoring", by DE Ward et al.
Biotelemetry Patient Monitoring, vol. 7, published in 1980).
[0084] Additionally, the medical treatment process to actually
obtain a cardiac rhythm monitoring device and initiate monitoring
is typically very complicated. There are usually numerous steps
involved in ordering, tracking, monitoring, retrieving, and
analyzing the data from such a monitoring device. In most cases,
cardiac monitoring devices used today are ordered by a cardiologist
or a cardiac electrophysiologist (EP), rather than the patient's
primary care physician (PCP). This is of significance since the PCP
is often the first physician to see the patient and determine that
the patient's symptoms could be due to an arrhythmia. After the
patient sees the PCP, the PCP will make an appointment for the
patient to see a cardiologist or an EP. This appointment is usually
several weeks from the initial visit with the PCP, which in itself
leads to a delay in making a potential diagnosis as well as
increases the likelihood that an arrhythmia episode will occur and
go undiagnosed. When the patient finally sees the cardiologist or
EP, a cardiac rhythm monitoring device will usually be ordered. The
monitoring period can last 24 to 48 hours (Holter monitor) or up to
a month (cardiac event monitor or mobile telemetry device). Once
the monitoring has been completed, the patient typically must
return the device to the clinic, which itself can be an
inconvenience. After the data has been processed by the monitoring
company or by a technician on-site at a hospital or office, a
report will finally be sent to the cardiologist or EP for analysis.
This complex process results in fewer patients receiving cardiac
rhythm monitoring than would ideally receive it.
[0085] To address some of these issues with cardiac monitoring, the
assignee of the present application developed various embodiments
of a small, long-term, wearable, physiological monitoring device.
One embodiment of the device is the Zio.RTM. Patch. Various
embodiments are also described, for example, in U.S. Pat. Nos.
8,150,502, 8,160,682 8,244,335, 8,560,046, and 8,538,503, the full
disclosures of which are hereby incorporated herein by reference.
Generally, the physiological patch-based monitors described in the
above references fit comfortably on a patient's chest and are
designed to be worn for at least one week and typically two to
three weeks. The monitors detect and record cardiac rhythm signal
data continuously while the device is worn, and this cardiac rhythm
data is then available for processing and analysis.
[0086] These smaller, long-term, patch-based physiological
monitoring devices provide many advantages over prior art devices.
At the same time, further improvements are desired. One of the most
meaningful areas for improvement is to offer more timely notice of
critical arrhythmias to managing clinicians. The hallmark of these
initial embodiments was that--for reasons of performance,
compliance and cost--the device only recorded information during
the extended wear period, with analysis and reporting occurring
after the recording completed. Thus, a desirable improvement would
be to add the capability of either real-time or timely analysis of
the collected rhythm information. While diagnostic monitors with
such timely reporting capabilities currently exist, they require
one or more electrical components of the system to be either
regularly recharged or replaced. These actions are associated with
reduced patient compliance and, in turn, reduced diagnostic yield.
As such, a key area of improvement is to develop a physiologic
monitor that can combine long-term recording with timely reporting
without requiring battery recharging or replacement.
[0087] Patient compliance and device adhesion performance are two
factors that govern the duration of the ECG record and consequently
the diagnostic yield. Compliance can be increased by improving the
patient's wear experience, which is affected by wear comfort,
device appearance, and the extent to which the device impedes the
normal activities of daily living. Given that longer ECG records
provide greater diagnostic yield and hence value, improvements to
device adhesion and patient compliance are desirable.
[0088] Signal quality is important throughout the duration of wear,
but may be more important where the patient marks the record,
indicating an area of symptomatic clinical significance. Marking
the record is most easily enabled through a trigger located on the
external surface of the device. However, since the trigger may be
part of a skin-contacting platform with integrated electrodes, the
patient can introduce significant motion artifacts when feeling for
the trigger. A desirable device improvement would be a symptom
trigger that can be activated with minimal addition of motion
artifact.
[0089] Further, it is desirable for the device to be simple and
cost effective to manufacture, enabling scalability at
manufacturing as well as higher quality due to repeatability in
process. Simplicity of manufacture can also lead to ease of
disassembly, which enables the efficient recovery of the printed
circuit board for quality-controlled reuse in another device.
Efficient reuse of this expensive component can be important for
decreasing the cost of the diagnostic monitor.
[0090] There remain clinical scenarios where still longer-duration
and lower-cost solutions may be a valuable addition to a portfolio
of cardiac ambulatory monitoring options. Inspiration for a
potential solution to these needs can be found in the continuous
heart rate sensing functionality that is increasingly being
incorporated in a variety of consumer health and fitness products,
including smart watches and wearable fitness bands. Although
continuous heart rate data can be used to provide the user with
information about their general fitness levels, it is more both
more challenging and valuable to use this data to provide
meaningful information related to their health and wellness. For
example, the ability to detect potential arrhythmias from
continuous heart rate data would enable consumer devices
incorporating heart rate sensing functionality to serve as
potential screening tools for the early detection of cardiac
abnormalities. Such an approach could be clinically valuable in
providing a long-term, cost-effective screening method for at-risk
populations, for example, heart failure patients at risk for Atrial
Fibrillation. Alternatively, this monitoring approach could be
helpful in the long-term titration of therapeutic drug dosages to
ensure efficaciousness while reducing side effects, for example, in
the management of Paroxysmal Atrial Fibrillation. Beyond cardiac
arrhythmia detection, the appropriate analysis of heart rate
information could also yield insight into sleep and stress
applications.
[0091] Long-term ambulatory monitoring with a physiologic device,
such as an adhesive patch, has a number of clinical applications,
particularly when timely information about the occurrence and
duration of observed arrhythmias can be provided during the
monitoring period. In terms of prevalence, particularly as driven
by an aging population, efficiently detecting Atrial Fibrillation
(AF) remains the most significant monitoring need. This need is not
just evident for patients presenting with symptoms, but also--given
the increased risk of stroke associated with this arrhythmia--for
broader, population-based monitoring of asymptomatic AF in
individuals at risk due to one or more factors of advanced age, the
presence of chronic illnesses like Heart Disease, or even the
occurrence of surgical procedures. For the latter group, both
perioperative and post-procedure monitoring can be clinically
valuable, and not just for procedures targeted at arrhythmia
prevention (for example, the MAZE ablation procedure, or hybrid
endo and epicardial procedures, both for treatment of AF), but also
for general surgeries involving anesthesia. For some applications,
the goal of ambulatory monitoring for Atrial Fibrillation will
sometimes be focused on the simple binary question of yes or
no--did AF occur in a given time period. For example, monitoring a
patient following an ablation procedure will typically seek to
confirm success, typically defined as the complete lack of AF
occurrence. Likewise, monitoring a patient post-stroke will be
primarily concerned with evaluating the presence of Atrial
Fibrillation.
[0092] However, even in those scenarios, if AF occurs, it may be
clinically meaningful to evaluate additional aspects to better
characterize the occurrence, such as daily burden (% of time in AF
each day), and duration of episodes (expressed, for example, as a
histogram of episode duration, or as the percentage of episodes
that extend beyond a specified limit, say six minutes), both either
in absolute terms or in comparison to prior benchmarks (for
example, from a baseline, pre-procedure monitoring result). Indeed,
measuring daily AF burden, evaluating AF episode duration, and
reviewing AF occurrence during sleep and waking periods, and
evaluating the presence of AF in response to the degree of a
patient's physical movement can be important in a variety of
clinical scenarios, including evaluating the effectiveness of
drug-based treatment for this arrhythmia.
[0093] Making this information available in a timely manner during
the monitoring period could allow the managing physician to
iteratively titrate treatment, for example, by adjusting the dosage
and frequency of a novel oral anticoagulant drug (NOAC) until
management was optimized. A further example of this management
paradigm is for the patient to be notified of asymptomatic
AF--either directly by the device through audible or
vibration-based alert, through notification from an application
connected to the device, or via phone, email or text-message
communication from the managing clinician--for the timely
application of a "pill in the pocket" for AF management.
[0094] The theme of timely management and/or intervention is
certainly evident in situations where clinically significant
arrhythmias are observed, for example, asymptomatic second-degree
and complete Heart Block, extended pauses, high-rate
supraventricular tachycardias, prolonged ventricular tachycardias,
and ventricular fibrillation. For example, the clinical scenario
where an extended pause or complete heart block causes Syncope is a
particularly significant case where the availability of a timely
and dependable monitoring method could reduce or even eliminate the
need for in-hospital monitoring of at-risk patients. The theme can
also extend to more subtle changes in morphology, for example, QT
prolongation in response to medications, which has been shown to
have significant cardiac safety implications. Timely awareness of
such prolongation could lead, for example, to early termination of
clinical studies evaluating drug safety and effectiveness or,
alternatively, to adjusting the dosage or frequency as a means to
eliminate observed prolongation.
Physiological Monitoring Devices
[0095] Referring to FIGS. 1A and 1B, perspective and exploded
profile views of one embodiment of a physiological monitoring
device 100 are provided. As seen in FIG. 1A, physiological
monitoring device 100 may include a flexible body 110 coupled with
a watertight, housing 115. As will be understood by one of skill in
the art, the housing as described herein and throughout this
specification, may be constructed from rigid or flexible materials,
thereby rendering the housing rigid, such as to resist deformation
or soft such as to flex and/or deform with force. Flexible body 110
(which may be referred to as "flexible substrate" or "flexible
construct") typically includes two wings 130, 131, which extend
laterally from housing 115, and two flexible electrode traces 311,
312, each of which is embedded in one of wings 130, 131. Each
electrode trace 311, 312 is coupled, on the bottom surface of
flexible body 110, with a flexible electrode (not visible in FIG.
1A). The electrodes are configured to sense heart rhythm signals
from a patient to which monitoring device 100 is attached.
Electrode traces 311, 312 then transmit those signals to
electronics (not visible in FIG. 1A) housed in housing 115. Housing
115 also typically contains a power source, such as one or more
batteries.
[0096] The combination of a highly flexible body 110, including
flexible electrodes and electrode traces 311, 312, with a very
housing 115 may provide a number of advantages. A key advantage is
high fidelity signal capture. The highly conformal and flexible
wings 130, 131, electrodes and traces 311, 312 limit the
transmission of external energy to the electrode-skin interface. If
motion is imparted to the housing 115, for example, the system of
conformal adhesion to the skin limits the extent to which that
motion affects the monitored signal. Flexible electrode traces 311,
312 generally may help provide conformal contact with the subject's
skin and may help prevent electrodes 350 (electrodes 350 are not
visible in FIG. 1, but are visible in FIG. 6A described below) from
peeling or lifting off of the skin, thereby providing strong motion
artifact rejection and better signal quality by minimizing transfer
of stress to electrodes 350. Furthermore, flexible body 110
includes a configuration and various features that facilitate
comfortable wearing of device 100 by a patient for fourteen (14)
days or more without removal. Housing 115, which typically does not
adhere to the patient in the embodiments described herein, includes
features that lend to the comfort of device 100. Hinge portions 132
are relatively thin, even more flexible portions of flexible body
110. They allow flexible body 110 to flex freely at the area where
it is joined to housing 115. This flexibility enhances comfort,
since when the patient moves, housing 115 can freely lift off of
the patient's skin. Electrode traces 311, 312 are also very thin
and flexible, to allow for patient movement without signal
distortion.
[0097] Referring now to FIG. 1B, a partially exploded view of
physiological monitoring device 100 illustrates component parts
that make up, and that are contained within, housing 115 in greater
detail. In this embodiment, housing 115 includes an upper housing
member 140, which detachably couples with a lower housing member
145. Sandwiched between upper housing member 140 and lower housing
member 145 are an upper gasket 370, and a lower gasket 360 (not
visible on FIG. 1B but just below upper gasket 370). Gaskets 370,
360 help make housing member and/or body 115 watertight when
assembled. A number of components of monitoring device 100 may be
housed between upper housing member 140 and lower housing member
145. For example, in one embodiment, housing 115 may contain a
portion of flexible body 110, a printed circuit board assembly
(PCBA) 120, a battery holder 150, and two batteries 160. Printed
circuit board assembly 120 is positioned within housing 115 to
contact electrode traces 311, 312 and batteries 160. In various
embodiments, one or more additional components may be contained
within or attached to housing 115. Some of these optional
components are described further below, in reference to additional
drawing figures.
[0098] Battery holder 150, according to various alternative
embodiments, may hold two batteries (as in the illustrated
embodiment), one battery, or more than two batteries. In other
alternative embodiments, other power sources may be used. In the
embodiment shown, battery holder 150 includes multiple retain tabs
and/or protrusions 153 for holding batteries 160 in holder 150.
Additionally, battery holder 150 includes multiple feet and/or
protrusions 152 to establish correct spacing of batteries 160 from
the surface of PCBA 120 and ensure proper contact with spring
fingers and/or contacts 235 and 236. Spring fingers 235 and 236 are
used in this embodiment rather than soldering batteries 160 to PCBA
120. Although soldering may be used in alternative embodiments, one
advantage of spring fingers 235 and 236 is that they allow
batteries 160 to be removed from PCBA 120 and holder 150 without
damaging either of those components, thus allowing for multiple
reuses of both Eliminating solder connections also simplifies and
speeds up assembly and disassembly of monitoring device 100.
[0099] In some embodiments, upper housing member 140 may act as a
patient event trigger. When a patient is wearing physiological
monitoring device 100 for cardiac rhythm monitoring, it is
typically advantageous for the patient to be able to register with
device 100 (for example, log into the device's memory) any cardiac
events perceived by the patient. If the patient feels what he/she
believes to be an episode of heart arrhythmia, for example, the
patient may somehow trigger device 100 and thus provide a record of
the perceived event. In some embodiments, trigger of perceived
events by the patient may initiate transmission of data associated
with the triggered event. In some embodiments, trigger of perceived
events may simply mark a continuous record with the location of the
triggered event. In some embodiments, both transmission of
associated data as well as marking of the continuous record may
occur. At some later time, the patient's recorded symptom during
the perceived event could be compared with the patient's actual
heart rhythm, recorded by device 100, and this may help determine
whether the patient's perceived events correlate with actual
cardiac events. One problem with patient event triggers in
currently available wearable cardiac rhythm monitoring devices,
however, is that a small trigger may be hard to find and/or
activate, especially since the monitoring device is typically worn
under clothing. Additionally, pressing a trigger button may affect
the electronics and/or the electrodes on the device in such a way
that the recorded heart rhythm signal at that moment is altered
simply by the motion caused to the device by the patient
triggering. For example, pressing a trigger may jar one or both of
the electrodes in such a way that the recorded heart rhythm signal
at that moment appears like an arrhythmia, even if no actual
arrhythmia event occurred. Additionally, there is a chance that the
trigger may be inadvertently activated, for instance while sleeping
or laying on the monitoring device.
[0100] In the embodiment shown in FIGS. 1A and 1B, however, housing
115 is sufficiently rigid, and flexible body 110 is sufficiently
flexible, that motion applied to housing 115 by a patient may
rarely or ever cause an aberrant signal to be sensed by the
electrodes. In this embodiment, the central portion of upper
housing member 140 is slightly concave and, when pressed by a
patient who is wearing device 100, this central portion depresses
slightly to trigger a trigger input on PCBA 120. Because the entire
upper surface of housing 115 acts as the patient event trigger,
combined with the fact that it is slightly concave, it will
generally be quite easy for a patient to find and push down the
trigger, even under clothing. Additionally, the concave nature of
the button allows it to be recessed which protects it from
inadvertent activations. Thus, the present embodiment may alleviate
some of the problems encountered with patient event triggers on
currently available heart rhythm monitors. These and other aspects
of the features shown in FIGS. 1A and 1B will be described in
further detail below.
[0101] Referring now to the embodiments in FIGS. 2A and 2B, printed
circuit board assembly 120 (or PCBA) may include a top surface 220,
a bottom surface 230, a patient trigger input 210 and spring
contacts 235, 236, and 237. Printed circuit board assembly 120 may
be used to mechanically support and electrically connect electronic
components using conductive pathways, tracks or electrode traces
311, 312. Furthermore, because of the sensitive nature of PCB A 120
and the requirement to mechanically interface with rigid body 115,
it is beneficial to have PCBA 120 be substantially rigid enough to
prevent unwanted deflections which may introduce noise or artifact
into the ECG signal. This is especially possible during patient
trigger activations when a force is transmitted through rigid body
115 and into PCBA 120. One way to ensure rigidity of the PCBA is in
some embodiments, to ensure that the thickness of the PCBA is
relatively above a certain value. For example, a thickness of at
least about 0.08 cm is desirable and, more preferably, a thickness
of at least about 0.17 cm is desirable. In this application, PCBA
120 may also be referred to as, or substituted with, a printed
circuit board (PCB), printed wiring board (PWB), etched wiring
board, or printed circuit assembly (PCA). In some embodiments, a
wire wrap or point-to-point construction may be used in addition
to, or in place of, PCBA 120. PCBA 120 may include analog circuits
and digital circuits.
[0102] Patient trigger input 210 may be configured to relay a
signal from a patient trigger, such as upper housing member 140
described above, to PCBA 120. For example, patient trigger input
210 may be a PCB switch or button that is responsive to pressure
from the patient trigger (for example, the upper surface of upper
housing portion 140). In various embodiments, patient trigger input
210 may be a surface mounted switch, a tactile switch, an LED
illuminated tactile switch, or the like. In some embodiments,
patient trigger input 210 may also activate an indicator, such as
an LED. Certain embodiments may involve a remotely located trigger
such as on a separate device or as a smart phone app.
[0103] One important challenge in collecting heart rhythm signals
from a human or animal subject with a small, two-electrode
physiological monitoring device such as device 100 described
herein, is that having only two electrodes can sometimes provide a
limited perspective when trying to discriminate between artifact
and clinically significant signals. For example, when a left-handed
patient brushes her teeth while wearing a small, two-electrode
physiological monitoring device on her left chest, the tooth
brushing may often introduce motion artifact that causes a recorded
signal to appear very similar to Ventricular Tachycardia, a serious
heart arrhythmia. Adding additional leads (and, hence, vectors) is
the traditional approach toward mitigating this concern, but this
is typically done by adding extra wires adhered to the patient's
chest in various locations, such as with a Holter monitor. This
approach is not consistent with a small, wearable, long term
monitor such as physiological monitoring device 100.
[0104] An alternate approach to the problem described above is to
provide one or more additional data channels to aid signal
discrimination. In some embodiments, for example, device 100 may
include a data channel for detecting patch motion. In certain
embodiments, an accelerometer or other suitable device may provide
patch motion by simply analyzing the change in magnitude of a
single axis measurement, or alternatively of the combination of all
three axes. The accelerometer may record device motion at a
sufficient sampling rate to allow algorithmic comparison of its
frequency spectrum with that of the recorded ECG signal. If there
is a match between the motion and recorded signal, it is clear that
the device recording in that time period is not from a clinical
(for example, cardiac) source, and thus that portion of the signal
can be confidently marked as artifact. This technique may be
particularly useful in the tooth brushing motion example
aforementioned, where the rapid frequency of motion as well as the
high amplitude artifact is similar to the heart rate and
morphology, respectively, of a potentially life-threatening
arrhythmia like Ventricular Tachycardia. Other suitable devices
described herein this section and elsewhere in the specification
may also be utilized to provide motion information.
[0105] In some embodiments, using the magnitude of all three axes
for such an analysis would smooth out any sudden changes in values
due to a shift in position rather than a change in activity. In
some embodiments, there may be some advantage in using a specific
axis of measurement such as along the longitudinal axis of the body
to focus on a specific type of artifact introduced by upward and
downward movements associated with walking or running. In a similar
vein, the use of a gyroscope in conjunction with the accelerometer
may provide further resolution as to the nature of the motion
experienced. While whole body movements may be sufficiently
analyzed with an accelerometer on its own, specific motion of
interest such as rotational motion due to arm movement is
sufficiently complex that an accelerometer alone might not be able
to distinguish.
[0106] In addition to detecting motion artifact, an accelerometer
tuned to the dynamic range of human physical activities may provide
activity levels of the patient during the recording, which can also
enhance accuracy of algorithmic true arrhythmia detection. Given
the single-lead limitation of device 100, arrhythmias that require
observation of less prominent waves (for example P-wave) in
addition to rate changes such as Supraventricular Tachycardia pose
challenges to both computerized algorithms as well as the trained
human eye. This particular arrhythmia is also characterized by the
sudden nature of its onset, which may be more confidently
discriminated from a non-pathological Sinus Tachycardia if a sudden
surge in the patient's activity level is detected at the same time
as the increase in heart rate. Broadly speaking, the provision of
activity information to clinical professionals may help them
discriminate between exercise-induced arrhythmia versus not. As
with motion artifact detection, a single-axis accelerometer
measurement optimized to a particular orientation may aid in more
specifically determining the activity type such as walking or
running. This additional information may help explain symptoms more
specifically and thereby affect the subsequent course of
therapeutic action.
[0107] In certain embodiments, an accelerometer with 3 axes may
confer advantages beyond what magnitude of motions can provide.
When the subject is not rapidly moving, 3-dimensional accelerometer
readings may approximate the tilt of PCBA 120, and therefore body
orientation relative to its original orientation. The original body
orientation can be assumed to be in either an upright or supine
position which is required for appropriate positioning and
application of the device to the body. This information may aid in
ruling out certain cardiac conditions that manifest as beat-to-beat
morphology changes, such as cardiac alternans where periodic
amplitude changes are observed, often in heart failure cases.
Similar beat-to-beat morphology changes are observable in healthy
subjects upon shift in body position due to the shift in heart
position relative to the electrode vector, for example from an
upright to a slouching position. By design, the single-channel
device 100 does not have an alternate ECG channel to easily rule
out potential pathological shifts in morphology, however,
correlation with shifts in body orientation will help explain these
normal changes and avoid unnecessary treatment due to false
diagnosis.
[0108] In some embodiments, the accelerometer may also be used as a
sleep indicator, based on body orientation and movement. When
presenting clinical events (for example, pauses), it is
diagnostically helpful to be able to present information in a
manner that clearly separates events that occurred during sleep
from those during waking hours. In fact, certain algorithms such as
for ECG-derived respiratory rate only make sense to run when the
patient is in a relatively motionless state and therefore subtle
signal modulation introduced by chest movement due to breathing is
observable. Respiratory rate information is useful as one channel
of information necessary to detect sleep apnea in certain patient
populations.
[0109] In certain embodiments, the accelerometer may also be used
to detect free-falls, such as fainting. With an accelerometer,
device 100 may be able to mark fainting (syncope) and other
free-fall events without relying on patient trigger. In some
embodiments, such free-fall event triggers may initiate
transmission of associated data. In order to allow timely detection
of such critical events, yet considering the battery and memory
limitations of a small, wearable device such as device 100,
acquisition of accelerometer readings may be done in bursts, where
only interesting information such as a potential free fall is
written to memory at a high sampling rate. An expansion of this
event-trigger concept is to use specific tapping motions on device
100 as a patient trigger instead of or in conjunction with the
button previously described. The use and detection of multiple
types of tapping sequences may provide better resolution and
accuracy into what exactly the patient was feeling, instead of
relying on the patient to manually record their symptom and
duration in a trigger log after the fact. An example of such added
resolution is to indicate the severity of the symptom by the number
of sequential taps.
[0110] Alternatively, in some embodiments, optical sensors may be
used to distinguish between device motion and patient body motion.
Further, in additional embodiments, the device may not require a
button or trigger. In still more embodiments, suitable devices
described herein this section or elsewhere in the specification may
also be used.
[0111] Another optional data channel that may be added to
physiological monitoring device 100 is a channel for detecting flex
and/or bend of device 100. In various embodiments, for example,
device 100 may include a strain gauge, piezoelectric sensor or
optical sensor to detect motion artifact in device 100 itself and
thus help to distinguish between motion artifact and cardiac rhythm
data. Yet another optional data channel for device 100 may be a
channel for detecting heart rate. For example, a pulse oximeter,
microphone or stethoscope may provide heart rate information.
Redundant heart rate data may facilitate discrimination of ECG
signals from artifact. This is particularly useful in cases where
arrhythmia such as Supraventricular Tachycardia is interrupted by
artifact, and decisions must be made whether the episode was
actually multiple shorter episodes or one sustained episode.
Another data channel may be included for detecting ambient
electrical noise. For example, device 100 may include an antenna
for picking up electromagnetic interference. Detection of
electromagnetic interference may facilitate discrimination of
electrical noise from real ECG signals. Any of the above-described
data channels may be stored to support future noise discrimination
or applied for immediate determination of clinical validity in
real-time.
[0112] With reference now to the embodiments of FIGS. 3A and 3B,
flexible body 110 is shown in greater detail. As illustrated in
FIG. 3A, flexible body 110 may include wings 130, 131, a thin
border 133 (or "rim" or "edge") around at least part of each wing
130, 131, electrode traces 311, 312, and a hinge portion 132 (or
"shoulder") at or near a junction of each wing 130, 131 with
housing 115. Also shown in FIG. 3A is upper gasket 370, which is
not considered part of flexible body 110 for this description, but
which facilitates attachment of flexible body 110 to housing
115.
[0113] Hinge portions 132 are relatively thin, even more flexible
portions of flexible body 110. They allow flexible body 110 to flex
freely at the area where it is joined to housing 115. This
flexibility enhances comfort, since when the patient moves, housing
115 can freely lift off of the patient's skin. Electrode traces
311, 312 are also very thin and flexible, to allow for patient
movement without signal distortion. Borders 133 are portions of
flexible body 110 that is thinner than immediately adjacent
portions and that provide for a smooth transition from flexible
body 110 to a patient's skin, thus preventing edge-lift and
penetration of dirt or debris below flexible body 110.
[0114] As shown in greater detail in FIG. 3B, flexible body 110 may
include multiple layers. As mentioned previously, in some
embodiments, upper gasket 370 and lower gasket 360 are not
considered part of flexible body 110 for the purposes of this
description but are shown for completeness of description. This
distinction is for ease of description only, however, and should
not be interpreted to limit the scope of the described embodiments.
Flexible body 110 may include a top substrate layer 300, a bottom
substrate layer 330, an adhesive layer 340, and flexible electrodes
350. Top and bottom substrate layers 300, 330 may be made of any
suitable, flexible material, such as one or more flexible polymers.
Suitable flexible polymers can include, but are not limited to,
polyurethane, polyethylene, polyester, polypropylene, nylon, teflon
and carbon impregnated vinyl. The material of substrate layers 300,
330 may be selected based on desired characteristics. For example,
the material of substrate layers 300, 330 may be selected for
flexibility, resilience, durability, breathability, moisture
transpiration, adhesion and/or the like. In one embodiment, for
example, top substrate layer 300 may be made of polyurethane, and
bottom substrate layer 330 may be made of polyethylene or
alternatively polyester. In some embodiments, substrate layers 300,
330 may be made of the same material. In yet another embodiment,
substrate layer 330 may contain a plurality of perforations in the
area over adhesive layer 340 to provide for even more breathability
and moisture transpiration. In various embodiments, physiological
monitoring device 100 may be worn continuously by a patient for as
many as 14-21 days or more, without removal during the time of wear
and with device 100 being worn during showering, exercising and the
like. Thus, the material(s) used and the thickness and
configuration of substrate layers 300, 330 affect the function of
physiological monitoring device 100. In some embodiments, the
material of substrate layers 300, 330 acts as an electric static
discharge (ESD) barrier to prevent arcing.
[0115] Typically, top and bottom substrate layers 300, 330 are
attached to one another via adhesive placed on one or both layers
300, 330. For example, the adhesive or bonding substance between
substrate layers 300, 330 may be an acrylic-based, rubber-based, or
silicone-based adhesive. In other alternative embodiments, flexible
body 110 may include more than two layers of flexible material.
[0116] In addition to the choice of material(s), the dimensions,
such as thickness, length and width, of substrate layers 300, 330
may be selected based on desired characteristics of flexible body
110. For example, in various embodiments, the thickness of
substrate layers 300, 330 may be selected to give flexible body 110
an overall thickness of between about 0.1 mm to about 1.0 mm.
According to various embodiments, flexible body 110 may also have a
length of between about 7 cm and 15 cm and a width of about 3 cm
and about 6 cm. Generally, flexible body 110 will have a length
sufficient to provide a necessary amount of separation between
electrodes 350. For example, in one embodiment a distance from the
center of one electrode 350 to the center of the other electrode
350 should be at least about 6.0 cm and more preferably at least
about 8.5 cm. This separation distance may vary, depending on the
application. In some embodiments, substrate layers 300, 330 may all
have the same thickness. Alternatively, the two substrate layers
300, 330 may have different thicknesses.
[0117] As mentioned above, hinge portions 132 allow the rigid body
115 to lift away from the patient while flexible body 110 remains
adhered to the skin. The functionality of hinge portions 132 is
critical in allowing the device to remain adhered to the patient
throughout various activities that may stretch and compress the
skin. Furthermore, hinge portions 132 allow for significantly
improved comfort while wearing the device. Generally, hinge
portions 132 will be sufficiently wide enough to provide adequate
lift of rigid body 115 without creating too large of a peel force
on flexible body 110. For example, in various embodiments, the
width of hinge portion 132 should be at least about 0.25 cm and
more preferably at least about 0.75 cm.
[0118] Additionally, the shape or footprint of flexible body 110
may be selected based on desired characteristics. As seen in FIG.
3A, wings 130, 131 and borders 133 may have rounded edges that give
flexible body 110 an overall "peanut" shape. However, wings 130,
131 can be formed in any number of different shapes such as
rectangles, ovals, loops, or strips. In the embodiment shown in
FIGS. 3A and 3B, the footprint top substrate layer 300 is larger
than the footprint of bottom substrate layer 330, with the
extension of top substrate layer 300 forming borders 133. Thus,
borders 133 are made of the same polyurethane material that top
layer 300 is made of. Borders 133 are thinner than an adjacent
portion of each wing 130, 131, since they include only top layer
300. The thinner, highly compliant rim and/or border 133 will
likely enhance adherence of physiologic monitoring device 100 to a
patient, as it provides a transition from an adjacent, slightly
thicker portion of wings 130, 131 to the patient's skin and thus
helps prevent the edge of device 100 from peeling up off the skin.
Border 133 may also help prevent the collection of dirt and other
debris under flexible body 110, which may help promote adherence to
the skin and also enhance the aesthetics of device 100. In
alternative embodiments, the footprint of substrate layers 300, 330
may be the same, thus eliminating borders 133.
[0119] While the illustrated embodiments of FIGS. 1A-3B include
only two wings 130, 131, which extend from housing 115 in
approximately opposite directions (for example, at a 180-degree
angle relative to each other), other configurations are possible in
alternative embodiments. For example, in some embodiments, wings
130, 131 may be arranged in an asymmetrical orientation relative to
one another and/or one or more additional wings may be included. As
long as sufficient electrode spacing is provided to permit
physiological signal monitoring, and as long as wings 130, 131 are
configured to provide extended attachment to the skin, any suitable
configuration and number of wings 130, 131 and electrode traces
311, 312 may be used. The embodiments described above have proven
to be advantageous for adherence, patient comfort and accuracy of
collected heart rhythm data, but in alternative embodiments it may
be possible to implement alternative configurations.
[0120] Adhesive layer 340 is an adhesive that is applied to two
portions of the bottom surface of bottom substrate layer 330, each
portion corresponding to one of wings 130, 131. Adhesive layer 340
thus does not extend along the portion of bottom substrate layer
330 upon which housing 115 is mounted. Adhesive layer 340 may be
made of any suitable adhesive, although certain adhesives have been
found to be advantageous for providing long term adhesion to
patient skin with relative comfort and lack of skin irritation. For
example, in one embodiment, adhesive layer 340 is a hydrocolloid
adhesive. In certain embodiments, the adhesive layer 340 is
comprised of a hydrocolloid adhesive that contains
naturally-derived or synthetic absorbent materials which take up
moisture from the skin during perspiration.
[0121] With reference now to FIG. 3B, each of the two portions of
adhesive layer 340 includes a hole, into which one of electrodes
350 fits. Electrodes 350 are made of flexible material to further
provide for overall conformability of flexible body 110. In one
embodiment, for example, flexible electrodes 350 may be made of a
hydrogel electrode 350. Electrodes 350 generally provide conformal,
non-irritating contact with the skin to provide enhanced electrical
connection with the skin and reduce motion artifact. In some
embodiments, hydrogel electrodes 350 may be punched into adhesive
layer 340, thus forming the holes and filling them with hydrogel
electrodes 350. In one alternative embodiment, electrodes 350 and
adhesive 340 may be replaced with an adhesive layer made of a
conductive material, such that the entire adhesive layer on the
underside of each wing 130, 131 acts as an electrode. Such an
adhesive layer may include a hybrid adhesive/conductive substance
or adhesive substance mixed with conductive elements or particles.
For example, in one embodiment, such an adhesive layer may be a
hybrid of a hydrogel and a hydrocolloid adhesive. Housing 115 of
FIG. 1A also protects the electronics and power source contained in
housing 115, enhances the ability of a patient to provide an input
related to a perceived cardiac event, and allows for simple
manufacturing and reusability of at least some of the contents of
housing 115. These and other features of physiological monitoring
device 100 are described in greater detail below.
[0122] As discussed above, in some embodiments, adhesive layer 340
may cover a portion of the underside of lower substrate layer 330,
such that at least a portion of the bottom side of flexible body
110 does not include adhesive layer 340. As seen in FIG. 3A, hinges
132 may be formed in the flexible body 110 as portions of each wing
130, 131 on which adhesive layer 340 is not applied. Hinge portions
132 are generally located at or near the junction of flexible body
110 with housing 115, and thus provide for flexing of device 100 to
accommodate patient movement. In some embodiments, hinge portions
132 may have a width that is less than that of adjacent portions of
wings 130, 131, thus giving device 100 its "peanut" shape mentioned
above. As shown in FIG. 8, as a subject moves, device 100 flexes
along with patient movement. Device flexion may be severe and is
likely to occur many times during long term monitoring. Hinge
portions 132 may allow for dynamic conformability to the subject,
while the rigidity of housing 115 may allow housing 115 to pop up
off the patient's skin during device flexion, thus preventing
peeling of the device 100 off of the skin at its edge.
[0123] Flexible body 110 further includes two electrode traces 311,
312 sandwiched between upper substrate layer 300 and lower
substrate layer 330. Each electrode trace 311, 312 may include an
electrode interface portion 310 and an electrocardiogram circuit
interface portion 313. As illustrated in the embodiments of FIGS.
3C and 3D, ECG circuit interface portions 313 are in physical
contact with spring fingers 237 and provide electrical
communication with PCBA 120 when device 100 or zoomed-in device
portion 101 is assembled. Electrode interface portions 310 contact
hydrogel electrodes 350. Thus, electrode traces 311, 312 transmit
cardiac rhythm signals (and/or other physiological data in various
embodiments) from electrodes 350 to PCBA 120.
[0124] The material and thickness of electrode traces 311, 312 are
important for providing a desired combination of flexibility,
durability and signal transmission. For example, in one embodiment,
electrode traces 311, 312 may include a combination of silver (Ag)
and silver chloride (AgCl). The silver and silver chloride may be
disposed in layers. For example, one embodiment of electrode traces
311, 312 may include a top layer of silver, a middle layer of
carbon impregnated vinyl, and a bottom (patient-facing) layer of
silver chloride. In certain embodiments, both top and bottom layers
of electrode traces 311, 312 may be made of silver chloride. In one
embodiment, the top and bottom layers may be applied to the middle
layer in the form of silver ink and silver chloride ink,
respectively. In an alternative embodiment, each electrode trace
may include only two layers, such as a top layer of silver and a
bottom layer of silver chloride. In various embodiments, the
material of a bottom layer of each electrode trace 311, 312, such
as AgCl, may be selected to match the chemistry of the hydrogel
electrodes 350 and create a half-cell with the body of the
subject.
[0125] The thickness of the electrode traces 311, 312 may be
selected to optimize any of a number of desirable properties. For
example, in some embodiments, at least one of the layers of
electrode traces 311, 312 can be of a sufficient thickness to
minimize or slow depletion of the material from an anode/cathode
effect over time. Additionally, the thickness may be selected for a
desired flexibility, durability and/or signal transmission
quality.
[0126] As mentioned above, in some embodiments, top gasket 370 and
bottom gasket 360 may be attached upper substrate 300 and lower
substrate 330 of flexible body 110. Gaskets 360, 370 may be made of
any suitable material, such as urethane, which provides a
watertight seal between the upper housing member 140 and lower
housing member 145 of housing 115. In one embodiment, top gasket
370 and/or bottom gasket 360 may include an adhesive surface. FIG.
3E depicts an embodiment where top gasket 370 includes tabs 371
that protrude away from the profile of top housing 140 while still
being adhered to upper substrate 300. The tabs 371 cover a portion
of electrode traces 311, 312 and provide a strain relief for the
traces at the point of highest stress where the flexible body meets
the housing.
[0127] With reference now to the embodiment of FIG. 4, upper
housing member 140 and lower housing member 145 of housing 115 are
shown in greater detail. Upper and lower housing members 140, 145
may be configured, when coupled together with gaskets 360, 370 in
between, to form a watertight enclosure for containing PCBA 120,
battery holder 150, batteries 160 and any other components
contained within housing 115. Housing members 140, 145 may be made
of any suitable material to protect internal components, such as
water-resistant plastic. In one embodiment, upper housing member
140 may include a rigid sidewall and/or hook 440, a light pipe 410
to transmit visual information from the LEDs on the PCBA through
the housing member, a slightly flexible top surface 420, and an
inner trigger member 430 extending inward from top surface 420. Top
surface 420 is configured to be depressed by a patient when the
patient perceives what he or she believes to be an arrhythmia or
other cardiac event. When depressed, top surface 420 depresses
inner trigger member 430, which contacts and activates trigger
input 210 of PCBA 120. Additionally, as discussed previously, top
surface 420 may have a concave shape (concavity facing the inside
of housing 115) to accommodate the shape of a finger. It is
believed that the design of upper housing member 140 isolates
activation of the trigger input 210 from electrodes 350, thereby
minimizing artifact in the data recording.
[0128] With continued reference to FIG. 4, lower housing member 145
may be configured to detachably connect with upper housing member
140 in such a way that housing members 140, 145 may be easily
attached and detached for reusability of at least some of the
component parts of monitoring device 100. In some embodiments, a
bottom surface 445 (patient facing surface) of lower housing member
145 may include multiple dimples 450 (or "bumps," "protrusions" or
the like), which will contact the patient's skin during use.
Dimples 450 may allow for air flow between bottom surface 445 and
the patient's skin, thus preventing a seal from forming between
bottom surface 445 and the skin. It is believed that dimples 450
improve comfort and help prevent a perception in currently
available devices in which the patient feels as if monitoring
device 100 is falling off when the housing 115 lifts off the skin
and breaks a seal with the skin. In certain embodiments, the bottom
surface 445 of lower housing member 145 may include multiple divots
(recesses instead of protrusions) to prevent a seal from
forming.
[0129] Referring now to the embodiment of FIG. 5A, battery holder
150 is shown in greater detail. Battery holder 150 may be made of
plastic or other suitable material, is configured to be mounted to
PCBA 120 and subsequently attached to housing 115, and is capable
of holding two batteries 160 (FIG. 1B). In alternative embodiments,
battery holder 150 may be configured to hold one battery or more
than two batteries. A plurality of protrusions 152 provide a stable
platform for batteries 160 to be positioned a fixed distance above
the surface of PCBA 120, avoiding unwanted contact with sensitive
electronic components yet providing for adequate compression of
spring contacts 235 (FIG. 5B). Protrusions 153 lock batteries 160
into position and resist the upward force on the batteries from
spring contacts 235. Battery holder 150 also positions batteries
appropriately 160 to provide for adequate compression of spring
contacts 236. Use of battery holder 150 in conjunction with spring
contacts 235 and 236 allows for batteries 160 to be electrically
connected to PCBA 120 while still having additional electronic
components between batteries 160 and PCBA 120 and maintain a very
compact assembly. Battery holder 150 may include a flexible hook
510 which engages a corresponding rigid hook 440 of upper housing
member 140. Under normal assembly conditions the flexible hook 510
remains securely mated with rigid hook 440. For disassembly,
flexible hook 510 can be pushed and bent using an appropriate tool
passed through top housing 140 causing it to disengage from rigid
hook 440 and subsequently allow top housing 140 to be removed.
[0130] With reference now to the embodiments of FIGS. 6A and 6B,
physiological monitoring device 100 is shown in the side view
cross-section. As shown in 6A, physiological monitoring device 100
may include flexible body 110 coupled with housing 115. Flexible
body 110 may include top substrate layer 300, bottom substrate
layer 330, adhesive layer 340 and electrodes 350. Electrode traces
311, 312 are also typically part of flexible body 110 and are
embedded between top substrate layer 300 and bottom substrate layer
330, but they are not shown in FIG. 6. Flexible body 110 forms two
wings 130, 131, extending to either side of housing 115, and a
border 133 surrounding at least part of each wing 130, 131. Housing
115 may include an upper housing member 140 coupled with a lower
housing member 145 such that it sandwiches a portion of flexible
body 110 in between and provides a watertight, sealed compartment
for PCBA 120. Upper housing member 140 may include inner trigger
member 430, and PCBA may include patient trigger member 210. As
discussed previously, lower housing member 145 may include multiple
dimples 450 or divots to enhance the comfort of the monitoring
device 100.
[0131] It is desirable that PCBA 120 is sufficiently rigid to
prevent bending and introducing unwanted artifact into the signal.
In certain embodiments, an additional mechanism to reduce and
prevent unwanted bending of PCBA 120 may be used. This mechanism is
shown in FIG. 6B. Support post 460 is integral to lower housing 145
and is positioned directly under patient trigger input 210. During
patient symptom triggering, upper housing member 140 is depressed,
engaging inner trigger mechanism 430 and transmitting a force
through patient trigger input 210 into PCBA 120. The force is
further transmitted through PCBA 120 and into support post 460
without creating a bending moment, thus avoiding unwanted
artifact.
[0132] Referring to FIG. 7, in some embodiments, physiological
monitoring device 100 may include one or more additional, optional
features. For example, in one embodiment, monitoring device 100 may
include a removable liner 810, a top label 820, a device identifier
830 and a bottom label 840. Liner 810 may be applied over a top
surface of flexible member and/or body 110 to aid in the
application of device 100 to the subject. As is described in
further detail below, liner 810 may help support borders 133 of
flexible body 110, as well as wings 130, 131, during removal of one
or more adhesive covers (not shown) that cover adhesive surface 340
before use. Liner 810 may be relative rigid and/or firm, to help
support flexible body 110 during removal of adhesive covers. In
various embodiments, for example, liner 810 may be made of
cardboard, thick paper, plastic or the like. Liner 810 typically
includes an adhesive on one side for adhering to the top surface of
wings 130, 131 of flexible body 110.
[0133] Labels 820, 840 may be any suitable labels and may include
produce name(s), manufacturer name(s), logo(s), design(s) and/or
the like. They may be removable or permanently attached upper
housing member 140 and/or lower housing member 145, although
typically they will be permanently attached, to avoid unregulated
reuse and/or resale of the device by an unregistered user. Device
identifier 830 may be a barcode sticker, computer readable chip,
RFID, or the like. Device identifier 830 may be permanently or
removably attached to PCBA 120, flexible body 110 or the like. In
some embodiments, it may be beneficial to have device identifier
830 stay with PCBA 120.
[0134] Referring now to the embodiments of FIGS. 8A and 8B,
physiological monitoring device 100 generally includes hinge
portions 132 at or near the juncture of each wing 130, 131 with
housing 115. Additionally, each wing 130, 131 is typically adhered
to the patient via adhesive layers 340, while rigid body 115 is not
adhered to the patient and is thus free to "float" (for example,
move up and down) over the patient's skin during movement and
change of patient position. In other words, when the patient's
chest contracts, housing pops up or floats over the skin, thus
minimizing stress on device 100, enhancing comfort, and reducing
the tendency of wings 130, 131 to peel off of the skin. The
advantage provided by the combination of the floating rigid body
115 and the adhered wings 130, 131 is illustrated in FIGS. 8A and
8B. In FIG. 8A, a patient is sleeping, and in FIG. 8B, a patient is
playing golf. In both examples, monitoring device 100 is squeezed
together by the patient's body, causing housing 115 to float above
the skin as wings 130, 131 move closer together. This advantage of
a floating, non-attached portion of a physiological monitoring
device is described in further detail in U.S. Pat. No. 8,560,046,
which was previously incorporated by reference.
[0135] Referring now to FIGS. 9A-9F, one embodiment of a method for
applying physiological monitoring device 100 to the skin of a human
subject is described. In this embodiment, before the first step
shown in FIG. 9A, the patient's skin may be prepared, typically by
shaving a small portion of the skin on the left chest where device
100 will be placed and then abrading and/or cleaning the shaved
portion. As shown in FIG. 9A, once the patient's skin is prepared,
a first step of applying device 100 may include removing one or
both of two adhesive covers 600 from adhesive layers 340 on the
bottom surface of device 100, thus exposing adhesive layers 340. As
illustrated in FIG. 9B, the next step may be to apply device 100 to
the skin, such that adhesive layer 340 adheres to the skin in a
desired location. In some embodiments, one adhesive cover 600 may
be removed, the uncovered adhesive layer 340 may be applied to the
skin, and then the second adhesive cover 600 may be removed, and
the second adhesive layer 340 may be applied to the skin.
Alternatively, both adhesive covers 600 may be removed before
applying device 100 to the skin. While adhesive covers 600 are
being removed, liner 810 acts as a support for flexible body 110,
provides the physician or other user with something to hold onto,
and prevents flexible body 110 and borders 133 of flexible body 110
from folding in on themselves, forming wrinkles, and so forth. As
described above, liner 810 may be made of a relatively stiff, firm
material to provide support for flexible body 110 during
application of device 100 to the skin. Referring to FIG. 9C, after
device 100 has been applied to the skin, pressure may be applied to
flexible body 110 to press it down onto the chest to help ensure
adherence of device 100 to the skin.
[0136] In a next step, referring to FIG. 9D, liner 810 is removed
from (for example, peeled off of) the top surface of flexible body
110. As shown in FIG. 9E, once liner 810 is removed, pressure may
again be applied to flexible body 110 to help ensure it is adhered
to the skin. Finally, as shown in FIG. 9F, upper housing member 140
may be pressed to turn on physiological monitoring device 100. This
described method is only one embodiment. In alternative
embodiments, one or more steps may be skipped and/or one or more
additional steps may be added.
[0137] In certain embodiments, when a desired monitoring period has
ended, such as about 14 to 21 days in some cases, a patient (or
physician, nurse or the like) may remove physiological monitoring
device 100 from the patient's skin, place device 100 in a prepaid
mailing pouch, and mail device 100 to a data processing facility.
At this facility, device 100 may be partially or completely
disassembled, PCBA 120 may be removed, and stored physiological
data, such as continuous heart rhythm information, may be
downloaded from device 100. The data may then be analyzed by any
suitable method and then provided to a physician in the form of a
report. The physician may then discuss the report with the patient.
PCBA 120 and/or other portions of device 100, such as housing 115,
may be reused in the manufacture of subsequent devices for the same
or other patients. Because device 100 is built up as a combination
of several removably coupled parts, various parts may be reused for
the same embodiment or different embodiments of device 100. For
example, PCBA 120 may be used first in an adult cardiac rhythm
monitor and then may be used a second time to construct a monitor
for sleep apnea. The same PCBA 120 may additionally or
alternatively be used with a differently sized flexible body 110 to
construct a pediatric cardiac monitor. Thus, at least some of the
component parts of device 100 may be interchangeable and
reusable.
[0138] In further embodiments described in greater detail below,
the monitoring data may be transmitted wirelessly or through other
communication mediums to be analyzed, rather than requiring
physical shipment of the device for analysis and reporting.
[0139] Advantageously, physiological monitoring device 100 may
provide long term adhesion to the skin. The combination of the
configuration of flexible and conformal body 110, the watertight,
low profile configuration of housing 115, and the interface between
the two allows device 100 to compensate for stress caused as the
skin of the subject stretches and bends. As a result, device 100
may be worn continuously, without removal, on a patient for as many
as 14 to 21 days or more. In some cases, device 100 may be worn for
greater or less time, but 14 to 21 days may often be a desirable
amount of time for collecting heart rhythm data and/or other
physiological signal data from a patient.
[0140] One or more of the various components of the physiological
monitoring device 100 may be alternatively configured or
substituted with embodiments of components disclosed elsewhere
herein. For example, in some embodiments, the electrodes 350 and/or
flexible body 110 may be configured to deliver one or more
therapeutic drugs to the patient's skin. The one or more
therapeutic agents may be configured to combat skin irritation,
itchiness, and/or bacterial growth; may be configured to induce or
block histamine release; and/or may comprise anesthetic qualities,
any of which may improve patient compliance and/or prolong the
duration of wear of the physiological monitoring device 100. The
therapeutic agents may serve alternative or additional therapeutic
purposes as well. In some embodiments, the therapeutic agents may
be incorporated directly into the adhesive layer 340. For example,
the therapeutic agents may be mixed into a hydrocolloid solution
during fabrication of the adhesive layer 340. The therapeutic
agents may be configured to elute from the adhesive layer 340 into
contact with the patient's skin. The adhesive layer 340 can be
configured to provide controlled release of the drug. For instance,
the adhesive layer 340 may be configured to release the drug
gradually and/or at a substantially constant rate over a period of
time (e.g., over about: 1 week, 2 weeks, 3 weeks, 4 weeks, 5 weeks,
6 weeks, 7 weeks, 8 weeks, 9 weeks, 10 weeks, etc.). The adhesive
layer 340 may comprise perforations and/or a microporous structure
configured to facilitate diffusion of the one or more therapeutic
agents through the thickness of the adhesive layer 340. In some
embodiments, the therapeutic agents may be incorporated into one or
more overlaying support layers of the flexible body 110, such as
the top substrate layer 300 and/or the bottom substrate layer 330.
The support layers of the flexible body 110 may comprise pockets or
containers configured to store the one or more therapeutic agents.
The pockets may be in fluid communication with the adhesive layer
340 through perforations formed in the substrate layer or through
pores or channels formed in the substrate layers. In some
embodiments, the one or more therapeutic agents may diffuse through
the adhesive layer 340 to reach the skin. In some embodiments, the
perforations in the substrate layers may extend through the
adhesive layer 340 to the surface of the patient's skin. In some
embodiments, the electrodes 350 or flexible body 110 may be
configured to include antimicrobial agents to inhibit the growth of
microorganisms. The agents may include coatings or embedded
ingredients in the adhesive or electrode gel materials. These
antimicrobial agents may be configured for release gradually and/or
at a substantially constant rate over a period of time (e.g., over
about: 1 day, 3 days, 5 days, 1 week, 2 weeks, 3 weeks, 4 weeks, 5
weeks, 6 weeks, 7 weeks, 8 weeks, 9 weeks, 10 weeks, 1 month, 3
months, 5 months, 1 year, 3 years, 5 years, etc.). The adhesive
layer 340 may comprise perforations and/or a microporous structure
configured to facilitate diffusion of the one or more therapeutic
agents through the thickness of the adhesive layer 340.
Alternately, the antimicrobial properties may be intrinsic to the
structure of the adhesive, gels or any substrate or support layer.
In some embodiments, the electrodes 350 or flexible body 110 may be
configured to release deodorant or perfume components to limit odor
arising from long-term wear. Similar to therapeutic and
antimicrobial agents described above, the components could be
configured to release over time and/or diffuse through the
thickness of the adhesive or gel layers.
[0141] FIGS. 10A-10C schematically illustrate alternative examples
of trace layer 609. The trace layer 609 may comprise an electrical
trace 611, 612 for each electrode 350 (such as shown in FIG. 3B) of
the physiological monitoring device 100. The electrical traces 611,
612 may be disposed on (e.g., printed onto) a non-conductive
insulating layer 613. In some embodiments, the insulating layer 613
may comprise a polyester, such as polyethylene terephthalate (PET)
and/or another non-conductive polymer. One or more of the
electrical traces 611, 612 may be disposed on the same insulating
layer 613. The insulating layer 613 may be configured to maintain a
separation between the electrical traces 611, 612 that are coupled
to distinct electrodes 350. The electrical traces 611, 612 may
extend from the electrodes 350 into the housing 115 to make
electrical contact with the PCBA 120. In some embodiments, such as
embodiments in which the physiological monitoring device 100
comprises two opposite wings 130, 131 arranged generally collinear
with one another, the electrical traces 611, 612 may extend
generally collinearly along a direction defining a longitudinal
axis of the device. A transverse axis may be defined substantially
perpendicular to the longitudinal axis. The longitudinal axis
and/or the transverse axis may substantially bisect the housing 115
of the physiological monitoring device 100.
[0142] Each trace 611, 612 may extend from an electrode contact
area configured to contact an electrode 350 along a connecting
portion of the trace layer 609 to a housing area configured to be
received within the housing 115 (e.g., between an upper housing 140
and a lower housing 145, such as shown above in FIG. 7 and below in
FIGS. 12-13B). The housing area of the trace layer 609 may have an
area generally configured to match the perimeter of the upper
housing 140 and lower housing 145 where the housings meet (or as
described below in relation to the embodiments of FIGS. 12A-15I,
such as 640 and 645). For instance, the trace layer 609 may
comprise a generally circular housing area. The trace layer 609 may
have a plurality of holes 616 extending between upper and lower
surfaces of the trace layer 609. The holes 616 may allow mechanical
elements (e.g., posts as described elsewhere herein) to pass
through, such as mechanical elements which couple or mate the upper
housing 140 and the lower housing 145. The holes 616 may be
disposed generally along a perimeter of the housing area of the
trace layer 609. The holes 616 may extend through only the
insulating layer 613 and not the electrical traces 611, 612. At
least some of the holes 616 may be configured in dimension to
substantially match the size of one or more mechanical mating
elements (e.g., posts) such that passage of the one or more
mechanical mating elements through the holes 616 may help stabilize
the orientation of the trace layer 609 and/or may help secure the
trace layer 609 to the housing 115. The housing area of the trace
layer 609 may comprise a large central hole through which
components in the upper housing 140 may directly contact components
in the lower housing 145 (or as described below in relation to the
embodiments of FIGS. 12A-15I, such as 640 and 645). The housing
area of the electrical traces 611, 612 may be disposed on opposite
sides of the insulating layer 613 within the housing area of the
trace layer 609. The trace layer 609 may extend generally along the
longitudinal axis between the electrode contact areas. The
connecting portions of the trace layer 609 between the electrode
contact areas and the housing areas may comprise a width along the
transverse direction less than that of the electrode contact areas
and/or the housing areas of the trace layer 609.
[0143] The electrical traces 611, 612 may be disposed (e.g.,
printed and/or applied in any suitable manner) on one or both sides
(top and bottom) of the insulating layer 613. The electrical traces
611, 612 may comprise any of the conductive materials discussed
elsewhere herein. For instance, in some embodiments, the electrical
traces 611, 612 may comprise a layer of silver (Ag) printed on the
insulating layer 613. In embodiments, the electrode interface
portion 310 of the electrical traces 611, 612 may comprise a layer
of silver chloride (AgCl) in addition to or alternatively to the
layer of silver or other conductive material generally used for the
traces 611, 612, as described elsewhere herein. In some
embodiments, the layer of silver chloride or other electrode
interface material may be printed over the top of the layer of
silver or other conductive layer of the electrical traces 611, 612.
Silver may provide a more isotropic conductance than silver
chloride, which may provide better lateral conductance in an x- and
y-directions but worse vertical conductance along a z-direction
(transverse to the longitudinal and lateral axes). In some
embodiments, the electrical traces 611, 612 may be disposed
primarily on one side of the insulating layer 613 (e.g., the bottom
side or patient-facing side). For instance, the electrode interface
portion 310 and portions of the traces 611, 612 along the
connecting portion of the trace layer 609 may be disposed on only a
single side, but the electrocardiogram circuit interface portion
313 of the traces 611, 612 may be positioned on the opposite side
of the trace layer 609. Positioning the electrode interface portion
310 and electrocardiogram circuit interface portion 313 on opposite
sides of the trace layer 609 may allow for facile interfacing
between the electrical traces 611, 612 and PCBA 120, which may be
positioned opposite the trace layer 609 from the patient's skin to
minimize the amount of space occupied by the housing 115 between
the patient and the trace layer 609. In certain embodiments, the
trace layer 609 may comprise one or more vias 619 formed in through
holes of the trace layer 609 that extend through the insulating
later 613. The through holes may be formed through the conductive
material electrical traces 611, 612 and filled with the same and/or
a different conductive material to form the vias 619 which conduct
electric signals from one side of the trace layer 609 to the other.
The vias 619 may simplify the design and construction of the trace
layer 609 by avoiding the use of bends in metal components. In some
embodiments, conductive rivets may be used in addition to or
alternatively to the conductive vias 619. The electrocardiogram
circuit interface portion 313 of the traces 611, 612 may comprise
relatively larger surface areas than the traces 611, 612 along the
connecting portion of the trace layer 609 in order to provide
sufficient contact area for electrical contacts to electrically
couple the traces 611, 612 to the PCBA 120.
[0144] As shown in FIG. 10B, in some embodiments, one or more
resistors 614 may be disposed within the electrical traces 611,
612. The resistors 614 may comprise a conductive material of
increased resistance over the conductive material(s) (e.g., silver
and/or silver chloride) used to generally conduct electricity
between the electrodes 350 and the PCBA 120. For example, the
resistors 614 may comprise carbon and/or increased amounts of
carbon as compared to the electrical traces 611, 612. In some
embodiments, the resistors may have a resistance that is at least
approximately about: 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100
kiloohms (k.OMEGA.). The material of the resistor 614 may be
selected to reduce or minimize "popcorn" noise or 1/f noise. As
shown in FIGS. 10A-10C, the resistors 614 may intersect the
conductive path of the electrical traces 611, 612 between the
electrode interface portion 310 and the electrocardiogram interface
portion 313 such that they are disposed in-line with the conductive
material of the electrical traces 611, 612. The resistors 614 may
be disposed on a housing portion of the trace layer 609 such that
they are enclosed within the housing 115. The resistors 614 may be
disposed (e.g., printed) onto the substrate layer 613 in the same
manner or a different manner from the conductive material of the
electrical traces 611, 612. The resistors 614 may replace resistors
that would otherwise be disposed on the PCBA 120, thereby
potentially providing space-saving advantages. In some embodiments,
the resistors 614 may be used to reduce the current that travels
along the electrical circuit formed by the body and the interfacing
electrodes 350. The resistors 614 may act as a safety feature that
allows the physiological monitoring device 100 to be suitable for
use with a patient.
[0145] Returning to FIG. 10A, in some embodiments, the electrode
interface portions 310 may comprise a central aperture 617. The
central aperture 617 may be generally circular or any suitable
shape, for example an oval, square, triangle, rectangle, or
suitable polygonal shape. The central aperture 617 may provide for
improved moisture management. For example, moisture trapped between
the electrode 350 and the skin of the patient may be able to
transpire through the electrode (e.g., a hydrogel electrode) and
evaporate through the central aperture 617 and/or transpire through
breathable substrate layers positioned over central layer.
Improving moisture management may inhibit delamination and increase
the duration of wear of the physiological monitoring device
allowing for longer use. In some embodiment, the trace layer 609
may comprise a plurality of central apertures 617 positioned over
the top surface of the electrode 350. The cumulative surface area
of the one or more central apertures and/or vias 619 may be
balanced relative to the surface area of the electrode 350 to
prevent dry-out of hydrogel electrodes 350 and/or to attenuate
fluctuations in conductivity that may occur as the electrode
delaminates from the skin, since the metal is more conductive than
the hydrogel. In some embodiments, no substrate layers may be
positioned over the trace layer 609 or any overlying substrate
layers may comprise corresponding apertures positioned over the
central aperture 617 such that at least a portion of the upper
surface of the electrode 350 is exposed to the ambient environment.
In some embodiments, the diameter of the central aperture 617 may
be somewhat smaller than an outer diameter of the electrode 350
such that the trace layer 609 is seated on top of a top surface of
the electrode 350. An electrical connection may be formed between
an upper surface of the electrode and a lower surface of the trace
layer 609 via the electrode interface portion 310 of the electrical
trace 611, 612. In some embodiments, the diameter of the central
aperture 617 substantially matches the outer diameter of the
electrode 350 such that the electrode 350 may be received within
the central aperture 617. An electrical connection may be formed
between lateral edges of the conductive traces 611, 612 and the
lateral sides of the electrode 350 in addition or alternatively to
interactions between other portions and surfaces. In some
embodiments, the electrode 350 (e.g., a hydrogel electrode or any
suitable electrode) may be formed in situ within the central
aperture and/or swelled within the central aperture 617. The
electrode 350 may be swelled to have a diameter slightly larger
than the diameter of the central aperture 617 such that a
compressive force induces sufficient contact between the trace
layer 609 and the electrode 350.
[0146] FIG. 10A illustrates an example of a trace layer 609. FIG.
10B depicts a close-up of the inset A in FIG. 10A. As shown in FIG.
10A, the connecting portions of the trace layer 609 may
substantially bisect the hydrogel electrode 350 and/or the
electrode interface portion 310 of the traces 611, 612. The
electrical traces 611, 612 may be substantially linear along the
connecting portion of the trace layer 609 as shown in FIG. 10A. In
some embodiments, one or more of the electrical traces 611, 612 may
comprise a plurality of bends. The plurality of bends may produce a
zig-zag or accordion-like configuration which allows the one or
more of the electrical traces 611, 612 to better absorb tensile
and/or compressive strains along the longitudinal axis. FIG. 10C
illustrates another example of a trace layer 609. The trace layer
609 may not be symmetrical about the transverse and/or the
longitudinal axis as shown in FIG. 10C. In some embodiments, the
electrode interface portion 310 of one trace 611 may be configured
to be positioned higher up on the patient's body than the electrode
interface portion 310 of the other trace 612. The electrode
interface portions 310 may extend away from the portion of the
traces 611, 612 along the connecting portion of the trace layer 609
in lateral directions parallel to the transverse axis. The
electrode interface portions 310 may extend away from the
connecting portions in opposite directions. In some embodiments,
the entire trace 611 may be configured to be positioned higher up
on the patient's body than the opposing trace 612 as shown in FIG.
10C. The connecting portions of the trace layer 609 may be
substantially parallel but may be offset along the transverse axis
such that the connecting portions are not collinear. In some
embodiments, both the connecting portions may be offset and the
electrode interface portions 310 of the different traces 611, 612
may extend in opposite directions as shown in FIG. 10C. The lateral
offsetting of the electrodes 350 along the transverse axis may be
configured to appropriately position the electrodes as shown in
FIGS. 9A-9F while allowing the transverse axis to remain parallel
to the height of a patient.
[0147] In some embodiments, the electrode interface portions 310 of
one or more of the traces 611, 612 may be configured as a closed
loop of the trace layer 609 which extends 360 degrees to enclose
the central aperture 617. The trace layer 609 along the loop may
comprise a substantially uniform width which may be the same width
as the trace layer 609 along the connecting portion. In certain
embodiments, the width may be nonuniform. The electrical trace 611,
612 may extend along the entire circumference of the loop or may
extend only partially along the loop such that the electrical trace
611, 612 does not form a closed loop with itself.
[0148] In some embodiments, the physiological monitoring device 100
may comprise a battery terminal connector 650 configured to
physically connect the two opposite terminals of a battery. FIGS.
11A-11E schematically depict two examples of a battery terminal
connector 650. FIG. 11B depicts an inner surface of a battery
terminal connector 650 configured to contact the battery terminals
and FIG. 11A depicts an outer surface of the battery terminal
connector 650 opposite the surface depicted in FIG. 11B. FIG. 11D
depicts an inner surface of another example of a battery terminal
connector 650 configured to contact the battery terminals and FIG.
11C depicts an outer surface of the battery terminal connector 650
opposite the surface depicted in FIG. 11D. FIG. 11E illustrates a
side view of a battery 160 to which a battery terminal connector
650 has been coupled (e.g., adhered). The battery terminal
connector 650 may be configured to electrically connect to each of
the terminals of a battery 160 and to functionally reposition
electrical access to the battery terminals. The battery terminal
connector 650 may be configured to connect the terminals of a
coin-style battery or a battery comprising opposing top and bottom
sides in which one terminal is positioned on the top side and the
opposite terminal is positioned on the bottom side. In certain
embodiments, the battery terminal connector 650 may be configured
to position electrical access to both terminals of the battery on a
single side of the battery (e.g., the top side) in order to
simplify the electrical coupling of each terminal to the PCBA 120.
Accordingly, the battery terminal connector 650 may comprise a
first portion 655 (e.g., a bottom portion), a top portion 657
(e.g., a top portion), and a connecting portion 656 joining the
first portion 655 and the second portion 657. At least the
connecting portion 656 of the battery terminal connector 650 may be
sufficiently flexible such that the connecting portion 656 may
bend, fold, or wrap around a lateral side of the battery 160
between top and bottom surfaces of the battery 160.
[0149] The battery terminal connector 650 may comprise an
insulating layer 651 and two conductive battery traces 652, 653.
Each of the battery traces 652, 653 may be configured to contact
one of the two battery terminals. The insulating layer 651 may be
configured to maintain a separation between the two battery traces
652, 653, thereby insulating the battery traces 652, 653 from one
another. The insulating layer 651 may be configured to prevent at
least one of the battery traces 652, 653 from contacting the
battery terminal electrically coupled to the other battery trace.
The insulating layer 651 may be formed of a non-conductive
material. For instance, the insulating layer 651 may comprise a
polyethylene such as polyethylene terephthalate (PET) or other
suitable non-conductive polymers. The battery traces 652, 653 may
be formed of a highly conductive material configured to
electronically connect the battery terminals to the circuitry of
the physiological monitoring device 100. For instance, the battery
traces 652, 653 may comprise silver or copper (e.g., tin-plated
copper foil). At least portions of the inner surface of the battery
terminal connector 650 may be adhered to the battery terminals
using a conductive adhesive (e.g., a conductive acrylic adhesive)
configured to electrically couple each of the battery terminals to
one of the battery traces 652, 653.
[0150] The battery terminal connector 650 may comprise any suitable
arrangement of the battery traces 652, 653 and the insulating layer
651. In various embodiments, one of the battery traces 652 may
extend from a first side of the battery (e.g., a bottom side) to
the second side of the battery (e.g., the top side). The first
battery trace 652 may be exposed on the inner surface of the
battery terminal connector 650 on the first side of the battery 160
and exposed on only the outer surface of the battery terminal
connector 650 on the second side of the battery 160. The second
battery trace 653 may be disposed on only the second side of the
battery 160. The second battery trace 653 may be exposed on both
the inner surface and the outer surface of the battery terminal
connector 650 on the second side of the battery 160. The PCBA 120
may be configured to form electrical contacts with both of the
battery traces 652, 653 on the outer surface of the battery
terminal connector 650 as described elsewhere herein. The
insulating layer 651 may be disposed on at least the second side of
the battery 160 to separate the battery traces 652, 653 on the
second side of the battery 160 and to insulate the first battery
trace 652 from the battery terminal on the second side of the
battery 160. In embodiments, the insulating layer 651 may be
disposed on the inner surface of the battery terminal connector 650
along the connecting portion 656 and/or along at least portions of
the first side of the battery 160 (e.g., the bottom portion). The
insulating layer 651 may be disposed on the outer surface of the
battery terminal connector 650 along the connecting portion 656
and/or the first side of the battery 160 (e.g., the bottom
portion).
[0151] Returning to FIGS. 11A-11B, in some embodiments, the second
battery trace 653 may be disposed (e.g., printed or via other
suitable means) on the outer surface of the battery terminal
connector 650 but may comprise an extension 654 extending beyond an
edge of the insulating layer 651 such that the battery terminal on
the second side of the battery 160 may electrically contact the
extension 654 of the second battery trace 653 and the electric
current may be transferred to the outer surface of the battery
terminal connector 650 via the extension 654. In some embodiments,
as shown in FIGS. 11C-11D, the second battery trace 653 may be
disposed (e.g., printed) on the inner surface and the outer surface
of the battery terminal connector 650. The second battery trace 653
may sandwich a portion of the insulating layer 651. The battery
terminal connector 650 may comprise through holes filled with
conductive material to form vias electrically connecting the second
battery trace 653 on the inner surface and the outer surface of the
battery terminal connector such that electrical current may be
transferred from the second side of the battery though the battery
terminal connector 650 to an outer surface of the battery terminal
connector 650. In some embodiments, vias may also electrically
connect the first battery trace 652 between an inner surface and an
outer surface of the battery terminal connector 650. Conductive
rivets may be used in addition to or alternatively to the
conductive vias disclosed herein. FIGS. 11F through 11I depict an
example of a battery terminal connector 650 configured to contact
the battery terminals. FIG. 11F depicts the outer surface of the
battery terminal connector 650 prior to application of
non-conductive coverlay and/or layer 658 (as shown in FIG. 11H),
while FIG. 11G depicts the inner surface of the battery terminal
connector 650 prior to addition of adhesive 660 (as shown in FIG.
11I). In some embodiments, a second non-conductive layer 658 may
cover the first battery trace 652 and the connecting portion 656 on
the outside surface of the battery terminal connector 650. In
certain embodiments, the battery terminal connector 650 may have at
least one protruding tab 659 to positionally fix the battery
terminal connector and battery assembly inside of the device
housing. There may be one, two, three, four, or more protruding
tabs. One of skill in the art will understand that the protruding
tabs may be shaped in any suitable manner, such as a curved shape
or an angular shape.
[0152] FIGS. 12A-12G illustrate multi-perspective views of another
example of an upper housing 640. FIG. 12A depicts a partially
exploded view of the upper housing 640. In some embodiments, the
upper housing 640 may have a circular, ovoid, obround, rectangular,
square, or any other suitable profile shape in the horizontal
plane. The upper housing 640 may comprise a flexible upper frame
642 and a rigid shell 643. FIG. 12B shows a perspective view of the
flexible upper frame 642. FIG. 12C shows a side view of the
flexible upper frame 642. FIG. 12D shows a top view of the flexible
upper frame 642. The rigid shell 643 may be more rigid than the
flexible upper frame 642. For example, the rigid shell 643 may be
formed from a hard plastic (e.g., a polycarbonate such as
Makrolon.TM.) and the flexible upper frame 642 may be formed from a
softer rubber (e.g., Santoprene.TM.). The upper housing 640 may
comprise a button 644 forming at least a portion of a top surface
of the upper housing 640 and enclosing the internal components of
the housing 615 from above. The button 644 may be a separate piece
that is assembled with the flexible upper frame 642 and rigid shell
643 to form the upper housing 640, as shown in FIG. 12A. The button
644 may be relatively rigid relative to the flexible upper frame
642. In some embodiments, the button 644 may be formed from the
same material as the rigid shell 643. The button 644 may be
securely attached to the flexible upper frame 642 by any suitable
means (e.g., using adhesive, detents, snap fits, etc.) such that
the button 644 is configured as "floating" button over the internal
space of the upper housing 640. In some embodiments, the flexible
upper frame 642 may be overmolded over at least a portion of the
upper and lower surfaces of the button 644. Overmolding may be used
to secure the button 644 to the rigid shell 643. In some
embodiments, the button 644 may be entirely encased within the
flexible upper frame 642.
[0153] The rigid shell 643 may form a lateral surface of the upper
housing 640 (e.g., a circumference), as shown in FIG. 12A. The
rigid shell 643 may form an outer annular portion or an outer
perimeter of a top surface of the upper housing 640, as shown in
FIG. 12A. The flexible upper frame 642 may be overmolded to the
rigid shell 643. The flexible upper frame 642 may join the rigid
shell 643 to the button 644 as described elsewhere herein. The
flexible upper frame 642 may fill an annular gap in a top surface
of the upper housing 640 between the outer perimeter formed by the
rigid shell 643 and the button 644 forming a flexible border to the
button 644. The flexible upper frame 642 may be configured to be
biased in a manner that allows the button 644 to be depressed in a
downward direction relative to the rigid shell 643 to actuate
trigger 210. In some embodiments, the lower surface of the button
644 may be shaped to have a convex surface or other protrusion
configured to actuate the trigger input 210. In some embodiments, a
protrusion (e.g., an upside-down dome, pillar, or any suitable
shape) may be attached to a lower surface of the button 644. The
protrusion may accentuate the trigger actuation such that less
strain is required to actuate the trigger input 210. The protrusion
may be made of metal and/or plastic.
[0154] In some embodiments, the button 644 may be configured as a
cantilever button rather than a floating button, in which a
cantilever arm connects the button 644 to a lateral side (e.g., an
inner diameter) of the rigid shell 643. The cantilever arm may be
concealed by the flexible upper frame 642 such that the button 644
nonetheless externally appears as a floating button. In some
embodiments, the button 644 may not be a floating button but may be
integral with or directly joined to the rigid shell 643. The button
644 may be semi-rigid but comprise sufficient flexibility such that
the button 644 can be elastically deformed. The button 644 may
comprise a raised and/or convex configuration (e.g., a dome-like
configuration) when unbiased. The button 644 may be configured such
that the shape of the button 644 can be elastically deformed to
actuate the trigger input 210. For instance, a dome may be at least
partially inverted at or near an apex of the dome, such that the
center of the domed button 644 extends downward within the space
enclosed by the upper housing 640 to actuate the trigger input 210.
In some embodiments, upon reaching a threshold strain, the dome may
snap or buckle into an inverted configuration in which less
pressure is required to continue depressing the dome. The buckling
or snapping effect may be configured to provide a useful tactile
indication of trigger 210 actuation. In some embodiments, upon
release of pressure, the dome may snap back to its unbiased
configuration. In some embodiments, the domed button 644 may
include a conductive material or be coated in a conductive surface,
and the domed body may make direct contact with electrical
terminals on the PCBA 120 to actuate a trigger input without need
for an additional trigger input button 210 on the PCBA. In certain
embodiments, the button 644 may be rigid, but is attached to an
elastically deformable snap dome that makes contact direct contact
with electrical terminals on the PCBA 120 while providing tactile
feedback to the user. In some embodiments, the semi-rigid button
644 may be snapped into the rigid shell 643 such as through a lip
seal (the button 644 may be attached over an o-ring). In some
embodiments, the button 644 may be ultrasonically welded or sealed
onto the rigid shell 643. In some embodiments, the button 644 may
be formed as a thinned-out portion of the upper surface of the
rigid shell 643. In some embodiments, the button 644 may be formed
from a soft material, such as a thermoplastic elastomer, configured
to fold, flex, and/or rebound. The button 644 may comprise a hard
external surface piece mounted onto the softer material for the
user to press and/or a hard internal surface piece mounted onto the
softer material for contacting the trigger input 210. In some
embodiments, the softer material for contacting the trigger input
may include a soft conductive piece (such as a conductive foam
pill) enabling trigger input by shorting pads or traces on the PCBA
without requiring an explicit button component on the PCBA. In some
embodiments, the button 644 may be configured similarly to a
computer keyboard button. For instance, the button 644 may be
configured to sit on one or more support members that surround the
trigger input 210 and hold the button 644 over the trigger input
210 in a biased non-contacting position. In some embodiments, the
electrical signal indicating button depression may be depressed
through to the printed circuit board, through a flex circuit
attached to the button or through electrical traces applied to the
rigid shell 643. These electrical traces may be applied via laser
direct structuring, plating to a plateable substrate applied in a
secondary mold process, or printing via aerosol jet, inkjet or
screen printing of conductive materials.
[0155] The flexible upper frame 642 may comprise an upper rim 642a
configured to interface with the top surface of the rigid shell
643, as described elsewhere herein, and a lower rim 642b. The lower
rim 642b may comprise a larger diameter than the upper rim 642a.
The upper rim 642a and/or the lower rim 642b may comprise annular
(e.g., ring-shaped) configurations. The lower rim 642b may be
configured to interface with the lower surface of the lateral
sidewall of the rigid shell 643 (e.g., via overmolding or a snap
fit). An inner diameter of the lower rim 642b may be configured to
interface with an outer diameter of the PCBA 120 (e.g., via a snap
fit). The lower rim 642b may functionally couple the PCBA 120 to
the rigid shell 643. In some embodiments, the lower rim 642b may be
approximately the same rigidity as the upper rim 642a. In some
embodiments, the lower rim 642b may be more rigid than the upper
rim 642a. The upper rim 642a may be joined to the lower rim 642b by
one or more vertical ribs 642c. A plurality of ribs 642c may be
spaced (e.g., substantially uniformly) around the periphery of the
upper housing 640. The ribs 642c may help retain the PCBA 120
within the upper housing. In some embodiments, the PCBA 120 may be
configured with grooves in the peripheral edge of the PCBA 120 to
at least partially receive one or more of the ribs 642c. The ribs
642c may at least partially conform to the shape of the PCBA 120.
The ribs 642c may help absorb shock that would otherwise be
transmitted to the PCBA 120 and could, for instance, potentially
cause motion artifacts. Some of the ribs 642c may not join the
upper rim 642a and the lower rim 642b. Some of the ribs 642c may
extend upward from the bottom rim 642b but do not attach to the
upper rim 642a, as shown in FIGS. 12B-12D. Some of the ribs 642c
may extend downward from the upper rim 642a but do not attach to
the lower rim 642b. In some embodiments, only a single rib 642c
connects the upper rim 642a and the lower rim 642b, as shown in
FIGS. 12B-12D. In some embodiments, the upper rim may not connect
to the lower rim, or one of the two rings may be omitted
entirely.
[0156] In some embodiments, one or more connecting ribs 642c may be
circumferentially positioned substantially opposite the trigger
input 210. The one or more connecting ribs and/or frames 642 may
act as a fulcrum or pivot point about which the upper rim 642a and
the button 644 are depressed. The fulcrum-like arrangement may
allow deeper depression of the button 644 on the side of the PCBA
120 comprising the trigger input 210. In some embodiments, one or
more fulcrum posts may extend upward (e.g., from the PCBA 120)
vertically beneath the button 644. The fulcrum posts may be spaced
around a periphery beneath the lower surface of the button 644. The
fulcrum posts may have a height shorter than that of the trigger
input 210. The fulcrum posts may act as fulcrums and facilitate
biasing the lower surface of the button 644 toward the trigger
input 210 as the button 644 is depressed if the lower surface of
the button 644 contacts the fulcrum post. The fulcrum posts may be
particularly useful if the trigger input is positioned off-center
of the button 644 (e.g., on a periphery of the PCBA 120). In some
embodiments, the upper rim 642a of the flexible upper frame 642 may
be filled to form a continuous area such that the upper frame 642
may comprise an upper surface flush with the upper surface of the
rigid shell 643 and covering a central portion of the top surface
of the upper housing 640. In some embodiments, the button 644 may
be formed as an integral portion of the flexible upper frame 642
and may be approximately the same or even less rigid as the
remainder of the flexible upper frame 642. In some embodiments, a
button 644 (which may be flexible or rigid) may be coupled to an
upper surface of the flexible upper frame 644 (e.g., underneath the
upper surface). The button 644 may be attached to the upper surface
of the upper frame 642 (which may be flexible or rigid) via a
snap-fit, barb-fit, adhesive, suction force, etc. In some
embodiments, in order to minimize the potential for PCBA flex
during application of force on the input trigger by the button, the
upper housing 640 may include a stop feature that limits the travel
of the button 644 to minimize stress to the board. Such a stop
feature could also be implemented as a component on the PCBA, for
example as a non-active molded component that is press-fit on the
PCBA or an active component such as an antenna that is soldered to
the board but has a deliberate extension to enable limiting the
button's travel.
[0157] FIG. 12E depicts a perspective view of an inner surface of
the upper housing 640. In some embodiments, the upper housing 640
may comprise downward extending columns 641 configured for securing
or helping to secure the upper housing 640 to a lower housing 645.
The columns 641 may be spaced (e.g., substantially uniformly)
around a periphery of the upper housing 640. The columns 641 may
have channels configured to receive and retain posts 646 extending
from a lower housing 645 as described elsewhere herein (e.g., via a
press fit or an interference fit). The columns 641 may be formed as
part of the rigid shell 643. The columns 641 may be formed
integrally with the rigid shell 643. The columns 641 may be
positioned inward of the lower rim 642b of the flexible upper frame
and/or housing 640. One or more of the columns 641 may be merged
together with an inner diameter of the rigid shell 643, as shown in
FIG. 12E. One or more of the columns 641 may be spaced inward from
the inner diameter of the rigid shell 643. The columns 641 may
extend to a height above that of the inner diameter of the upper
housing 640 as shown in FIG. 12E, to approximately the same height
of the inner diameter of the upper housing 640, or below the height
of the inner diameter of the upper housing 640. The flexible upper
frame 642 may extend to a height above that of the inner diameter
of the rigid shell 643, to approximately the same height of the
inner diameter of the rigid shell 643, or below the height of the
inner diameter of the rigid shell 643 as shown in FIG. 12E. In
certain embodiments, and as described above, button 644 may flex as
an integrated part of the housing and/or shell 643. In such an
embodiment, upper rim 642a is no longer necessary. A window may be
added to button 644 covered in a thin layer of semi-transparent
material to allow for light transmission from an underlying
LED.
[0158] As shown in FIG. 12F, top 714 and bottom 716 portions of the
housing may be positioned above and below the flexible body 718. As
shown in FIG. 6D2, in embodiments, a gasket 719 may be positioned
between the upper housing 714 and lower housing 716, co-molded into
one or more of the housings. The gasket may compress down on the
adhesive assembly and a ridged interface (shown below in FIG. 12G)
or another gasket on the opposite housing to provide waterproofing
to the internal electronics hardware. As depicted in FIG. 12G, a
ridge 721 may be positioned on an upper edge of the lower housing
716, the ridge 721 configured to press into the adhesive layer
and/or the gasket 719. One of skill in the art will understand that
the ridge 721 may be of any suitable shape, for example such as an
edged ridge as depicted in FIG. 721. In some examples, the ridge
may be rounded, square, and/or polygonal. In certain examples, the
height of the ridge may be about 0.01 mm to 0.5 mm, about 0.05 mm
to 0.4 mm, about 0.1 mm to 0.3 mm, about 0.1 mm to 0.2 mm, or about
0.15 mm such as about 0.13 mm.
[0159] FIGS. 13A-13B illustrate multi-perspective views of another
example of a lower housing 645. The lower housing 645 may be
configured to engage upper housing 640. FIG. 13A depicts a
perspective view of the lower housing 645 and FIG. 13B depicts a
side view of the lower housing 645. In some embodiments, the lower
housing 645 may comprise a plurality of posts 646 extending upward
from the main body of the lower housing 645 beyond an upper
peripheral edge configured to meet a lower peripheral edge of the
upper housing 640. The posts 646 may be configured to extend into
the internal space enclosed by the upper housing 640. In some
embodiments, the posts 646 may not extend beyond the upper
peripheral edge of the lower housing 645. In some embodiments, the
posts 646 may be configured to pass through the holes 616 in the
trace layer 609 and may help secure the trace layer 609 to the
lower housing 645 as described elsewhere herein. The plurality of
posts 646 may be configured to be received within and to mate with
an equal number of columns 641 positioned opposite the posts 646 in
the upper housing 640. For example, the plurality of posts 646 may
be configured to form a press-fit or an interference fit with the
plurality of columns 641 such that the posts 646 and columns 641
are configured to secure or lock together the upper housing 640 and
the lower housing 645. The engagement between the posts 646 and
columns 641 may resist separation forces between the upper housing
640 and the lower housing 645. Separation forces may be induced by
the spring 665 described elsewhere herein, counterforces from
compression of gaskets between the upper and lower housings 640,
645 to form a watertight seal, the transference of force from the
upper housing 640 to the lower housing 645 during actuation of the
trigger 210, etc. In some embodiments, some or all of the posts 646
may be arranged on the upper housing 640 and some or all of the
columns 641 may be arranged on the lower housing 645. In some
embodiments, the lower housing 645 may comprise one or more buckle
columns configured to contact a bottom surface of the PCBA 120 (or
a spring contact spacer as described elsewhere herein). The buckle
columns may be configured to trap the PCBA 120 in firm contact
against the upper housing 640, subsume the tolerance in the PCBA
120 thickness, and/or provide additional rigidity for inducing a
firm tactile response against the button 644 pressing forces. In
some embodiments, the lower housing 645 may be joined with the
upper housing 645 through alternate processes, such as ultrasonic
welding, potentially removing the need for press fit posts.
[0160] In some embodiments, the housing 115 may comprise a spring
665 configured to provide a consistent force bias the internal
components enclosed by the housing 115 into contact with each
other. The spring 665 may generally bias the components toward the
top and/or the bottom of the housing 115. The spring 665 may absorb
the tolerance stack of the internal components and maintain a
substantially consistent biasing and vertical positioning or
spacing between the components regardless of minor variations in
the size of the various internal components or fit with respect to
each other. The spring 665 may bias the PCBA 120 into contact with
hard stops formed in the upper housing 640 such that the PCBA is
able to provide a counterforce to resist the button pressing force
and allow actuation of the input trigger 210. In some embodiments,
the spring 665 may be a wave spring although other configurations
of springs (e.g., a coil spring) may be used. In some embodiments,
the spring 665 may be replaced by an elastomeric foam which may
provide dampening properties in addition to the abovementioned
properties. FIGS. 14A-14B illustrate orthogonal side views of an
example of a wave spring 665. The wave spring 665 may be configured
to be seated substantially along the internal diameter of the
housing 115. In some embodiments, the spring 665 may be configured
to be seated in the bottom of the lower housing 145 and to bias the
internal components upward toward the upper housing 140, as
described elsewhere herein.
[0161] FIGS. 15A-15I illustrate multiple views of another example
of a physiological monitoring device 600. The physiological
monitoring device 600 may comprise one or more of the components
described elsewhere herein. The physiological monitoring device 600
may comprise a housing 615 comprising an upper housing 640 and a
lower housing 645 which are configured to mate together sandwiching
a flexible body 610 between the upper housing 640 and the lower
housing 645. The flexible body 610 may comprise the trace layer 609
and one or more substrate layers forming the wings of the
physiological monitoring device 600. The wings may comprise
adhesive layers 340 and electrodes 350 as described elsewhere
herein. The rigid body and/or housing 615 may enclose a PCBA 120, a
flexible upper frame 642, a battery 160, a battery terminal
connector 650, a portion of the trace layer 609, a spring contact
spacer 632, and a spring 665.
[0162] FIG. 15A depicts a perspective view of an embodiment of the
physiological monitoring device 600. FIG. 15B depicts an exploded
view of the physiological monitoring device 600. FIG. 15C depicts a
side view of the housing 615 in which the rigid shell 643 and
button 644 of the upper housing 640 has been removed. FIG. 15D
depicts a side view of the housing 615 as shown in FIG. 15C with
flexible upper frame 642 additionally being removed. FIG. 15E
depicts a side view of the housing 615 as shown in FIG. 15D with
the lower housing 645 additionally being removed. FIG. 15F depicts
a side view of the housing 615 as shown in FIG. 15E with the
battery 160 and spring 665 additionally being removed. FIG. 15G
depicts a sectional view of the housing as shown in Figure with the
section taken between the circuit board 120 and the spring contact
spacer 632. FIG. 15H depicts a sectional view of the housing as
shown in FIG. 15G with the spring contact spacer 632 additionally
being removed. FIG. 15I depicts a side view of the housing 615 as
shown in FIG. 15H additionally including the PCBA 120.
[0163] The upper housing 640 and the lower housing 645 may sandwich
the flexible body 610 as described elsewhere herein. In some
embodiments, the flexible body 610 may comprise one or more
apertures 332 through extending through one or more of the
substrate layers to provide breathability and moisture management
and/or to facilitate drug delivery to the skin of the surface, as
described elsewhere herein. An upper gasket layers 360 and/or a
lower gasket layer 370 (not shown) may be provided on opposite
sides of the flexible body 610 (not shown). The gasket layers 360,
370 may be adhesive for adhering to the flexible body 610. A
compressible seal may be formed above and/or below the flexible
body 610. In some implementations, a compressive seal may be formed
with the flexible upper frame 642. The battery 160 may be
positioned below the flexible body 610 comprising the trace layer
609. The PCBA 120 may be positioned above the flexible body 610
comprising the trace layer 609. A battery terminal connector 650
may be adhered or otherwise coupled to the battery 160 such that
first and second battery traces 652, 653 are exposed on an outer
surface of the battery terminal connector 650 on a top side of the
battery 160. The first and second battery traces 652, 653 may be
exposed to the internal volume of the upper housing 640 through a
large central opening in the housing area of the trace layer 609 as
shown in FIG. 15H.
[0164] Electrical contact between the PCBA 120 and the first and
second battery traces 652, 653 and/or electrical contact between
the PCBA 120 and the electrocardiogram interface portions 313 of
the electrical traces 611, 612 may be established by spring
contacts 637, depicted in FIGS. 15G-15I. The spring contacts 637
may be coupled to the bottom surface of the PCBA 120 as seen in
FIG. 15I. The housing 615 may comprise a spring contact spacer 632
positioned below the PCBA 120 (not shown in FIG. 15I). In some
embodiments, the spring contact spacer 632 may be rigidly affixed
(e.g., adhered) to the bottom of the PCBA 120. In embodiments, the
spring contact spacer may be attached or integrated into the
flexible body 610. In some embodiments, the spring contact spacer
may be integrated into the battery terminal connector. The spring
contact spacer 632 may comprise a flat body and a plurality of
downward extending legs 633. The legs 633 may be configured to be
seated against a top surface and/or a lateral surface of the
battery 160, as shown in FIG. 15E, such that the spring contact
spacer 632 maintains a minimum separation distance between the
battery 160 and the PCBA 120 and provides sufficient space for the
spring contacts 637. The spring contact spacer 632 may comprise one
or more holes 634 through which the spring contacts 637 may extend
downward from the bottom surface of the PCBA 120, as depicted in
FIG. 15G. The lower housing 645 may comprise a spring 665, as
described elsewhere herein positioned below the battery 160 as
shown in FIG. 15E. The spring 665 may bias the battery 160 upward
and may bias the first and second battery traces 652, 653 into
physical and electrical contact with corresponding spring contacts
637. The electrocardiogram interface portions 313 of the traces
611, 612 may be seated on a top side of the battery 160 such that
biasing the battery 160 upward also biases the electrocardiogram
interface portions 313 of the traces 611, 612 into physical and
electrical contact with corresponding spring contacts 637. The
substantially consistent spacing between the traces and the PCBA
120 provided by the spring 665 and the spring contact spacer 632
may reduce, minimize, or eliminate noise in the electrical signal
caused by fluctuating degrees of electrical contact between the
spring contacts 637 and the traces. The assembly may comprise at
least one spring contact 637 for each of the first battery trace
652, second battery trace 653, first electrical trace 611, and
second electrical trace 612. The assembly may comprise more than
one spring contacts 637 for some or all of the traces. The spring
contacts 637 may be configured under compression induced by the
arrangement of the various components, including spring 665, to
establish an electrical pathway between each of the traces and the
PCBA 120. The compressive contact between the spring contacts 637
and the traces may be maintained even under nominal changes in the
separation distances between the traces and the PCBA 120 (e.g.,
caused by movement) since the spring contacts 637 may extend
further downward if the separation distance increases and the
biasing corresponding decreases. In some embodiments, the first and
second battery traces 652, 653 may be configured to be positioned
on an opposite side of the housing 615 from the first and second
electrical traces 611, 612 as shown in FIG. 15H. In some
embodiments, the spring contacts may be configured to carry
electrical signals from battery or electrocardiogram signals by
contacting electrical traces applied to the upper housing 640 or
the bottom housing 645. These electrical traces may be applied to
the housings through the use of laser direct structuring, plating
to a plateable substrate applied in a secondary mold process, or
printing via aerosol jet, inkjet or screen printing of conductive
materials. In some embodiments, RF antennas for wireless
communication (such as Bluetooth) could be configured through the
use of such electrical traces in the top housing 640 or bottom
housing 645.
[0165] FIGS. 16A-16D depict multiple views of an embodiment of a
physiological monitoring device 800, similar to the physiological
monitoring devices depicted in FIGS. 10A-15I, such as FIG. 15A.
Here, the physiological monitoring device includes a central
housing 802, comprising an upper housing 802 and a lower housing
806 sandwiched over flexible substrate 810. One of skill in the art
will understand that the housing may be constructed from any
suitable material disclosed herein, such as a rigid polymer or a
soft, flexible polymer. In some embodiments, the housing may
include an indicator 808, which may be in any suitable shape such
as an oval, a circle, a square, or a rectangle. The indicator may
comprise an LED light source (not shown) or any suitable light
source, which may be overlain by a transparent or translucent
viewing layer positioned against the inner surface of the upper
housing. The viewing layer may be constructed from thermoplastic
polyurethane or any suitable material. The indicator may be used to
indicate a status of the physiological monitoring device such as
the battery life of the physiological monitoring device. In some
embodiments, the indicator may indicate whether the physiological
monitoring device is collecting data, transmitting data, paused,
experiencing an error, or analyzing data. The indicator may display
any suitable color, for example red, amber, or green.
[0166] Extending outward from the housing are a plurality of wings
812. One of skill in the art will understand that although two
wings are depicted here, some embodiments of the physiological
monitoring device 800 may include more than two wings. As explained
elsewhere in the specification, the wings may be shaped in such a
way to improve adhesion to the skin and retention of the
physiological monitoring device against the skin. In embodiments,
the wings may asymmetric, with a greater portion of one wing (an
upper lobe) 814 lying above the longitudinal line and a greater
portion of another wing lying (a lower lobe) 816 below the
longitudinal line, thereby allowing the physiological monitoring
device to be positioned diagonally over the heart such that the
lower lobe is positioned lower than the heart when a patient is in
a standing position.
[0167] Extending outward from the housing and contained on or
within the wings are electrode traces 818, similar to the electrode
traces described elsewhere in the specification, such as with
respect to FIGS. 10A-10C and FIG. 15A. As explained elsewhere in
the specification, the electrode traces may be printed directly on
a flexible substrate which may be part of a multi-layer flexible
assembly 820. Additional printed lines 822 may surround the
electrode trace 818 for visual enhancement of the physiological
monitoring device, however said printed lines 822 may be printed on
a different layer than the flexible substrate on which the
electrode traces are printed. The printed lines may be printed such
that they blend with the shape of the electrode trace. As explained
elsewhere in the specification, the electrode trace may encircle a
series of breathing holes 824 which allow for air passage to an
underlying hydrogel. In embodiments, there may be one, two, three,
four, or more breathing holes. As explained elsewhere in the
specification, apertures 826 may extend through one or more layers
of the physiological monitoring device to provide breathability and
moisture management. In embodiments, an adhesive border layer 828
may extend outward from the wings, thereby allowing for improved
adhesion. FIG. 16B depicts the underside of the physiological
monitoring device 800 depicted in FIG. 16A. Here, lower housing 806
is clearly visible as are the electrode traces 818 and printed
lines 822 extending outward from the housing. FIGS. 16C and 16D
depict the physiological monitoring device 800 of FIGS. 16A-16B,
here including an externally facing top liner 826 and skin facing
patient release liner 828 overlying the wings and surrounding the
housing 802. Such release liners serve to protect the physiological
monitoring device 800 during storage, in particular to protect the
adhesive surfaces of the physiological monitoring device. In
embodiments, the liners may be shaped such that two sides meet to
form an opening for the housing to extend vertically past the
liners.
[0168] In some implementations, an abrader may be used to abrade
the skin of the patient prior to adhesion of the physiological
monitoring device 100, 600, 800 (such as described elsewhere in the
specification) to the patient. The abrader may be used to remove a
top layer of skin from the patient to improve long-term adhesion of
the physiological monitoring device 100, 600 and/or signal quality
form the physiological monitoring device 100, 600. FIGS. 17A and
17B schematically illustrate cross-sectional views of two examples
of an abrader 700. The abrader 700 may comprise a housing 702. The
housing 702 may serve as a handle by which the patient or another
person can hold and operate the abrader 700. In some embodiments,
additional elements, such as an elongated handle for example, may
extend from or otherwise be coupled to the housing 702. The abrader
700 may comprise a substantially flat abrading surface 704 for
abrading the skin. The abrading surface 704 may comprise a
generally large surface area. The abrading surface 704 may comprise
a rough surface and/or protrusions for abrading the skin. In some
embodiments, the housing 702 may entirely or substantially
circumferentially surround the abrading surface 704, as depicted in
FIGS. 17A and 17B. The housing 702 may substantially enclose the
abrading surface 704 during the abrasion procedure. The abrading
surface 704 may be coupled to the housing 702 via a compressible
member or biasing element 706. In some embodiments, the
compressible member 706 may be a spring as shown in FIG. 17A. In
some embodiments, the compressible member 706 may be a compressible
foam as depicted in FIG. 17B. The abrading surface 704 may be
configured to protrude beyond a bottom surface of the housing 702
in an unbiased configuration.
[0169] The amount of abrasion may depend on the amount of pressure
applied to the abrader 700. Higher degrees of pressure may result
in increased friction between the abrader 700 and the skin of the
patient resulting in more severe abrasion. Too much pressure may
result in patient discomfort or pain during and/or after the
abrasion procedure. Too little pressure may result in inadequate
abrasion. The compressible element 706 may help the user tune the
amount of pressure that is applied to the abrader 700. The abrader
700 may be configured such that exertion of a pressure beyond a
threshold of necessary pressure sufficiently biases the
compressible element 706 to an extent such that the abrasion
surface is withdrawn into the housing 702 and can no longer contact
the skin. In some embodiments, the abrader 700 may be finely tuned
such that when the bottom of the housing 702 is pressed into
contact with the skin it deforms the skin encircled by the housing
702 to an extent that the abrading surface 704 is still able to
make contact with the skin. The compressible element 706 may
provide a tuned amount of force at this level of compression to
achieve a desirable degree of abrasion. In some implementations, a
desirable amount of abrasion may be achieved when the abrading
surface 704 is fully protruding from the housing 702 such that the
housing does not come into substantial contact with the skin. In
some embodiments, an indicator can be used to indicate to the user
that a desired (e.g., a sufficient) amount of pressure has been
achieved. For example, the foam compressible member 706 may be
formed from an open-cell foam having an internal color and an
external color, distinct from the internal color. The foam may be
configured to be visible to the user. For instance, the housing may
comprise an annular configuration surrounding the foam compressible
member 706 such that the foam compressible member 706 is visible
from the top during the abrasion procedure, as depicted in FIG.
17B. The internal color of the foam may be visible when the
compressible member 706 is in an unbiased configuration. The
compressible member 706 may be configured such that upon achieving
a threshold degree of compression, the open cells are compressed or
closed sufficiently enough that the internal color becomes no
longer visible to the user. The color change in the foam may serve
as a visual indicator the user that sufficient pressure has been
achieved. The visibility of the internal color may indicate to the
user that he or she should exert more pressure.
[0170] In various alternative embodiments, the shape of a
particular physiological monitoring device may vary. The shape,
footprint, perimeter or boundary of the device may be circular, an
oval, triangular, a compound curve or the like, for example. In
some embodiments, the compound curve may include one or more
concave curves and one or more convex curves. The convex shapes may
be separated by a concave portion. The concave portion may be
between the convex portion on the housing and the convex portion on
the electrodes. In some embodiments, the concave portion may
correspond at least partially with a hinge, hinge region or area of
reduced thickness between the body and a wing.
[0171] While described in the context of a heart monitor, the
device improvements described herein are not so limited. The
improvements described in this application may be applied to any of
a wide variety of physiological data monitoring, recording and/or
transmitting devices. The improved adhesion design features may
also be applied to devices useful in the electronically controlled
and/or time released delivery of pharmacological agents or blood
testing, such as glucose monitors or other blood testing devices.
As such, the description, characteristics and functionality of the
components described herein may be modified as needed to include
the specific components of a particular application such as
electronics, antenna, power supplies or charging connections, data
ports or connections for down loading or off-loading information
from the device, adding or offloading fluids from the device,
monitoring or sensing elements such as electrodes, probes or
sensors or any other component or components needed in the device
specific function. In addition, or alternatively, devices described
herein may be used to detect, record, or transmit signals or
information related to signals generated by a body including but
not limited to one or more of ECG, EEG and/or EMG. In certain
embodiments, additional data channels can be included to collect
additional data, for example, device motion, device flex or bed,
heart rate and/or ambient electrical or acoustic noise.
[0172] The physiological monitors described above and elsewhere in
the specification may further be combined with methods and systems
of data processing and transmission that improve the collection of
data from the monitor. Further, the methods and systems described
below may improve the performance of the monitors by enabling
timely transmission of clinical information while maintaining the
high patient compliance and ease-of-use of the monitor described
above. For example, the methods and systems of data processing and
transmission described herein this section of elsewhere in the
specification may serve to extend the battery life of the monitor,
improve the accuracy of the monitor, and/or provide other
improvements and advantages as described herein this section or
elsewhere in the specification.
Device Monitoring and Clinical Analysis Platform
[0173] The systems and methods described in detail below, may
selectively extract, transmit, and analyze electrocardiographic
signal data and other physiological data from a wearable
physiological monitor, such as is described above. The systems and
methods described below can improve the performance of a wearable
physiological monitor that simultaneously records and transmits
data through multiple means. For example, selective transmission of
extracted data allows for decreased power consumption because the
wearable patch is not required to transmit all recorded data. By
sending extracted data, much of the analysis may be performed away
from the wearable device without requiring full on-board rhythm
analysis, which can also be highly power consumptive, reducing
battery life. Further, remote analysis without the power
constraints inherent to a wearable device may allow for greater
sensitivity and accuracy in analysis of the data. Decreased power
consumption serves to improve patient compliance because it
prolongs the time period between or even eliminates the need for
device replacement, battery changes or battery recharging during
the monitoring cycle. By decreasing battery consumption, longer
monitoring times may be enabled without device replacement, for
example, at least one week, at least two weeks, at least three
weeks, or more than three weeks.
[0174] FIG. 18 depicts a general overview of an embodiment of a
system 900 for inferring cardiac rhythm information from an R-R
interval time series 902, as may be generated by a continuous heart
rate monitoring device 904. The R-R interval time series 902
inputted to the system may include a series of measurements of the
timing interval between successive heartbeats. Typically, each
interval represents the time period between two successive R peaks
as identified from an ECG signal. R peaks are part of the QRS
complex, a combination of three graphical deflections typically
seen on an ECG, representing the depolarization of the left and
right ventricles of a mammal's heart. The R peak is generally the
tallest and most visible upward deflection on an ECG, and thus
makes for an appropriate reference point. However, in further
embodiments, any characteristic ECG fiducial point (such as the QRS
complex onset or offset) may be used in place of the R peak to
provide an estimate of the R-R interval time series. As described
above in relation to FIGS. 1 through 9 and throughout the
specification, the physical characteristics of the monitoring
device are constructed in such a way as to improve signal fidelity,
therefore the high signal fidelity allows for a high level of
confidence in accurately extracting R-R peak data.
[0175] The R-R interval time series 902 data may be extracted from
or received from a dedicated heart rate monitor such as a heart
rate chest strap or heart rate watch, or a wearable health or
fitness device 906, 908 that incorporates heart rate sensing
functionality. Alternatively, the R-R interval time series 902 may
be derived from a wearable patch 904 designed to measure an ECG
signal (for instance, by locating the R peaks in the ECG using a
QRS detection algorithm). Furthermore, the R-R interval time series
902 may be estimated from an alternative physiological signal such
as that obtained from photoplethysmography (PPG). In this scenario,
the peak-to-peak interval time series determined from the PPG
signal may be used as an accurate estimate of the R-R interval time
series.
[0176] In one aspect, a cardiac rhythm inference system 910 is
implemented as a cloud service or server-based system that exposes
an application programming interface (API) enabling R-R interval
time series data or other signal data to be transmitted to the
system (for instance, via HTTP) and the resulting cardiac rhythm
information to be returned to the calling software. The R-R
interval time series data 902 or other signal data may be
transmitted to the cloud service directly from the heart-rate
monitoring device itself, or indirectly via a smartphone 912,
tablet or other internet-enabled communication device 914 that can
receive data from the heart rate monitoring device in either a
wireless or wired manner. In addition, the R-R interval time series
data 902 or other signals may be transmitted from a server 916 that
stores the data for a number of users.
[0177] In some embodiments, a cardiac rhythm inference system 910
is provided through a software library that can be incorporated
into a standalone application for installation and use on a
smartphone, tablet or personal computer. The library may provide
identical functionality to that of the inference service, but with
R-R interval time series data 902 or other signal data transmitted
directly through a functional call, as opposed to through a web
service API.
[0178] In certain embodiments, a cardiac rhythm inference system
may accept a plurality of R-R interval time series measured from
devices of a given user 918, in addition to an individual R-R
interval time series 902. In this scenario, the system computes the
frequency and duration of each of the cardiac rhythm types inferred
from the collection of time series data. These results may then be
used to estimate confidence statistics for each type of cardiac
rhythm based on the frequency and duration of occurrence of that
rhythm across the various time series. In addition, the rhythm
confidence statistics may be updated in a sequential manner for
each separate call of the inference service. Furthermore, in some
embodiments, the cardiac rhythm information inferred by the system
may be provided back to the calling software only in the event that
the confidence score for a given rhythm type exceeds a
pre-determined threshold value.
[0179] In particular embodiments, a cardiac rhythm inference system
910 may accept additional sources of data, generally described as
alternate sensor channels, in addition to R-R interval time series
data, to enhance the accuracy and/or value of the inferred results.
One additional source of data includes user activity time series
data, such as that measured by a 3-axis accelerometer concurrently
with the R-R interval time series measurements. In addition, the
system may accept other relevant metadata that may help to improve
the accuracy of the rhythm analysis, such as user age, gender,
indication for monitoring, pre-existing medical conditions,
medication information, medical history and the like, and also
information on the specific day and time range for each time series
submitted to the system. Furthermore, the measurement device might
also provide some measure of beat detection confidence, for
example, for each R-Peak or for sequential time periods. This
confidence measure would be based on analysis the recorded signal
that, in typical embodiments, would not be recorded due to storage
space and battery energy requirements. Finally, in the particular
case that the R-R interval time series data are derived from an ECG
signal, the system may accept additional signal features computed
from the ECG. These features may include a time series of
intra-beat interval measurements (such as the QT or PR interval, or
QRS duration), or a time series of signal statistics such as the
mean, median, standard deviation or sum of the ECG signal sample
values within a given time period.
[0180] The various aspects described above could be used either
individually or in combination to provide an application providing
insights into an individual's health, stress, sleep, fitness and/or
other qualities.
[0181] Some embodiments concern a system for selective transmission
of electrocardiographic signal data from a wearable medical sensor.
Current wearable sensors, such as the iRhythm ZioPatch.TM. 904, and
further described above in relation to FIGS. 1-9, are capable of
recording a single-lead electrocardiogram (ECG) signal for up to
two weeks on a single battery charge. In many situations however,
it is desirable for the sensor to be able to transmit, in real-time
or near real-time, specific sections of the recorded ECG signal
with clinical relevance to a computer device, such as either a
smartphone 912 or an internet-connected gateway device 914 for
subsequent processing and analysis. In this way, the patient or
their physician can be provided with potentially valuable
diagnostic ECG information during the period that the patient wears
the sensor.
[0182] As described above, a significant challenge with this
approach is to manage the battery life of the wearable sensor
without requiring replacement or recharging, both of which reduce
user compliance. Each transmission of an ECG from the sensor to a
smartphone or local gateway device (using, for example, Bluetooth
Low Energy) results in a subsequent reduction in the total charge
stored in the sensor battery. Some embodiments of the present
disclosure, particularly those of FIGS. 17 to 24 address this issue
through the use of a novel hardware and software combination to
enable the selective transmission of clinically relevant sections
of ECG from a wearable sensor.
[0183] In certain embodiments, the wearable sensor incorporates
either a software, hardware or hybrid QRS detector that produces a
real-time estimate of each R-peak location in the ECG. The R-peak
location data is then used to compute an R-R interval time series
that is subsequently transmitted to a smartphone or gateway device
according to a predefined schedule (for example, once per hour). In
addition, a time stamp is also transmitted which stores the onset
time for the R-R interval time series relative to the start of the
ECG recording. Since the R-R interval time series for a given
section of ECG is significantly smaller (in terms of bytes
occupied) than the ECG signal itself, it can be transmitted with
considerably less impact on battery life.
[0184] In some embodiments of a second stage of the system, the R-R
interval time series together with the onset time stamp is
subsequently transmitted by the smartphone or gateway device to a
server. On the server, the R-R interval time series is used to
infer a list of the most probable heart rhythms, together with
their onset and offset times, during the period represented by the
time series data. The list of inferred heart rhythms is then
filtered according to specific criteria, such that only rhythms
matching the given criteria are retained after filtering. A measure
of confidence may also be used to assist in filtering the events in
a manner that might improve the Positive Predictivity of
detection.
[0185] In certain embodiments of a third stage of the system, for
each rhythm in the filtered rhythm set, the server transmits to the
smartphone or gateway device the onset and offset time for that
specific rhythm. In the event that the inferred rhythm duration
exceeds a pre-defined maximum duration, the onset and offset times
may be adjusted such that the resulting duration is less than the
maximum permissible duration. The onset and offset times received
by the gateway are then subsequently transmitted to the wearable
sensor, which in turn transmits the section of the recorded ECG
signal between the onset and offset times back to the gateway. This
section of ECG is then transmitted to the server where it can be
analyzed and used to provide diagnostic information to the patient
or their physician.
[0186] In some embodiments, the system fundamentally allows a
device worn for up to about: 14, 21, or 30 days or beyond without
battery recharging or replacement (both activities that reduce
patient compliance and, therefore, diagnostic value) to provide
timely communication of asymptomatic arrhythmia events. This
development is motivated by technology constraints: in order to
enable a small, wearable device that does not require battery
change or recharging while providing continuous arrhythmia analysis
with high accuracy, it is desirable to limit the complexity of
analysis performed on-board. Similarly, streaming of all of the
recorded ECG data to an off-board analysis algorithm may not be
practical without imposing greater power requirements. This
motivates a more creative "triage" approach where selected features
of the recorded ECG signal, including but not limited to R-R
intervals, are sent for every beat, allowing a customized algorithm
to locate a number (for example, 10) of 90-second events to request
from the device in full resolution to support comprehensive
analysis, for example, a resolution capable of supporting clinical
diagnosis.
[0187] In some embodiments, the system would provide the ability to
detect asymptomatic arrhythmias in a timely manner on a wearable,
adhesively affixed device that does not require frequent recharging
or replacement. This would be used to enhance the value of some
current clinical offerings, which only provide clinical insight
after the recording is completed and returned for analysis.
[0188] In certain embodiments, the system would allow actionable
clinical insight to be derived from data collected on low-cost,
easy-to-use consumer wearable devices that are otherwise only
focused on fitness and wellness. For example, the technology could
be used to create a very effective, low-cost screening tool capable
of detecting the presence of Atrial Fibrillation in the at-large
population. By using such a tool, not only would patients in need
of care be found more easily, but it may be done earlier and more
cost effectively, which lead to better outcomes--namely, through
reducing stroke risk by identifying AF more quickly.
[0189] In particular embodiments, the system may provide the
service through a downloadable application that, after receiving
customer consent for data access and payment approval, would
initiate access and analysis of heartbeat data stored from wearable
devices, either stored locally in a mobile device or in an online
repository. This data pull and analysis would happen through an
Algorithm API, and would result in a clinical finding being sent
back to the application to be provided to the user. If the data was
sufficient to support a "screening oriented" finding, for example,
"Likely presence of an irregular rhythm was detected", the
application would direct them to a cardiologist where a more
diagnostically focused offering, for example, the ZIO.RTM. Service,
could be provided to support clinical diagnosis and treatment. In
further embodiments, as also described elsewhere in the
specification, the system may trigger an alarm if a particular
measurement and/or analysis indicates that an alarm is needed.
[0190] Further examples of additional scenarios of clinical value
may include coupling ambulatory arrhythmia monitoring with a
blood-alcohol monitor to study the interaction of AF and lifestyle
factors. For example, ambulatory arrhythmia monitoring could be
coupled with a blood-glucose monitor to study the impact of
Hypoglycemia on arrhythmias. Alternatively, ambulatory arrhythmia
monitoring could be coupled with a respiratory rate and/or volume
monitor to study the interaction of sleep apnea and breathing
disorders. Further, there could be evaluation of the high rates of
supraventricular ectopic beats as a potential precursor for AF (for
example, 720 SVEs in 24-hour period).
Extraction, Transmission, and Processing Systems
[0191] FIG. 19 is a schematic illustration of an embodiment of a
system and method 1000 for a wearable medical sensor 1002 with
transmission capabilities, similar to the system and/or method
described above in relation to FIG. 19. In some embodiments, sensor
1002, which may be any type of sensor or monitor described herein
this section or elsewhere in the specification, continuously senses
an ECG or comparable biological signal 1004 and continuously
records an ECG or comparable biological signal 1004. In certain
embodiments, the sensing and/or recording steps may be performed
intermittently. The collected signal 1004 may then be continuously
extracted into one or more features 1006, representing example
features A, B, and C. The features are not intended to be samplings
of different temporal sections of the signal, instead (as will be
described in greater detail below) the different features may
correspond to different types or pieces of data such as R-peak
locations or R-peak amplitudes. The features of the ECG or
comparable biological signal are extracted to facilitate analysis
of the signal 1004 remotely. In certain embodiments, features are
extracted on a windowed basis, with the window size varying for
example between 1 hour or multiple hours to a few seconds. In
certain embodiments, the window may be at most: about 0.1 second,
about 1 second, about 2 seconds, about 3 seconds, about 5 seconds,
about 10 seconds, about 30 seconds, about 1 minute, about 5
minutes, about 30 minutes, about 1 hour, about 2 hours, about 4
hours, or more than 4 hours. The extraction windows may be
separated by various amounts of time if they are repeated. For
example, the extraction windows may be separated by at least: about
30 seconds, about 1 minute, about 5 minutes, about 30 minutes,
about 1 hour, about 3 hours, about 6 hours, about 12 hours, about
24 hours, about 48 hours, or more than three days. In certain
embodiments, the windowing sizes may vary depending on the feature
extracted. Feature extraction may be limited to one type or various
types of features, and features chosen for extraction may vary
depending on the nature of the signal observed.
[0192] A wide variety of different types of ECG or comparable
biological signal features may be extracted. For example, R-peak
locations may be extracted. In certain embodiments, the R-peak
locations are extracted via various methods such as: a Pan-Tompkins
algorithm (Pan and Tompkins, 1985), providing a real-time QRS
complex detection algorithm employing a series of digital filtering
steps and adaptive thresholding, or an analog R-peak detection
circuit comprising an R-peak detector consisting of a bandpass
filter, a comparator circuit, and dynamic gain adjustment to locate
R-peaks. The RR-intervals may be calculated from peak locations and
used as the primary feature for rhythm discrimination. In
embodiments, an R-peak overflow flag may be extracted. If more than
a certain number of R-peaks were detected during a given time
window such that not all data can be transmitted, a flag may be
raised by the firmware. Such an extraction may be used to eliminate
noisy segments from analysis, on the basis that extremely short
intervals of R-R are not physiologically possible. With similar
motivation, an R-peak underflow flag may be extracted to indicate
an unrealistically long interval between successive R peaks,
provided appropriate considerations for asystole are made in this
evaluation. In an alternative implementation with the same goal,
the lack of presence of R peaks in a prolonged interval could be
associated with a confidence measure, which would describe the
likelihood that the interval was clinical or artifact.
[0193] In general, the word "module," as used herein, refers to
logic embodied in hardware or firmware, or to a collection of
software instructions, possibly having entry and exit points,
written in a programming language, such as, for example, Python,
Java, Lua, C and/or C++. A software module may be compiled and
linked into an executable program, installed in a dynamic link
library, or may be written in an interpreted programming language
such as, for example, BASIC, Perl, or Python. It will be
appreciated that software modules may be callable from other
modules or from themselves, and/or may be invoked in response to
detected events or interrupts. Software modules configured for
execution on computing devices may be provided on a computer
readable medium, such as a compact disc, digital video disc, flash
drive, or any other tangible medium. Such software code may be
stored, partially or fully, on a memory device of the executing
computing device, such as the computing system 13000, for execution
by the computing device. Software instructions may be embedded in
firmware, such as an EPROM. It will be further appreciated that
hardware modules may be comprised of connected logic units, such as
gates and flip-flops, and/or may be comprised of programmable
units, such as programmable gate arrays or processors. The block
diagrams disclosed herein may be implemented as modules. The
modules described herein may be implemented as software modules,
but may be represented in hardware or firmware. Generally, the
modules described herein refer to logical modules that may be
combined with other modules or divided into sub-modules despite
their physical organization or storage.
[0194] Each of the processes, methods, and algorithms described in
the preceding sections may be embodied in, and fully or partially
automated by, code modules executed by one or more computer systems
or computer processors comprising computer hardware. The code
modules may be stored on any type of non-transitory
computer-readable medium or computer storage device, such as hard
drives, solid state memory, optical disc, and/or the like. The
systems and modules may also be transmitted as generated data
signals (for example, as part of a carrier wave or other analog or
digital propagated signal) on a variety of computer-readable
transmission mediums, including wireless-based and
wired/cable-based mediums, and may take a variety of forms (for
example, as part of a single or multiplexed analog signal, or as
multiple discrete digital packets or frames). The processes and
algorithms may be implemented partially or wholly in
application-specific circuitry. The results of the disclosed
processes and process steps may be stored, persistently or
otherwise, in any type of non-transitory computer storage such as,
for example, volatile or non-volatile storage.
[0195] The various features and processes described above may be
used independently of one another, or may be combined in various
ways. All possible combinations and subcombinations are intended to
fall within the scope of this disclosure. In addition, certain
method or process blocks may be omitted in some implementations.
The methods and processes described herein are also not limited to
any particular sequence, and the blocks or states relating thereto
can be performed in other sequences that are appropriate. For
example, described blocks or states may be performed in an order
other than that specifically disclosed, or multiple blocks or
states may be combined in a single block or state. The example
blocks or states may be performed in serial, in parallel, or in
some other manner. Blocks or states may be added to or removed from
the disclosed example embodiments. The example systems and
components described herein may be configured differently than
described. For example, elements may be added to, removed from, or
rearranged compared to the disclosed example embodiments.
[0196] Conditional language, such as, among others, "can," "could,"
"might," or "may," unless specifically stated otherwise, or
otherwise understood within the context as used, is generally
intended to convey that certain embodiments include, while some
embodiments do not include, certain features, elements and/or
steps. Thus, such conditional language is not generally intended to
imply that features, elements and/or steps are in any way required
for one or more embodiments or that one or more embodiments
necessarily include logic for deciding, with or without user input
or prompting, whether these features, elements and/or steps are
included or are to be performed in any particular embodiment. The
term "including" means "included but not limited to." The term "or"
means "and/or."
[0197] Any process descriptions, elements, or blocks in the flow or
block diagrams described herein and/or depicted in the attached
figures should be understood as potentially representing modules,
segments, or portions of code which include one or more executable
instructions for implementing specific logical functions or steps
in the process. Alternate implementations are included within the
scope of the embodiments described herein in which elements or
functions may be deleted, executed out of order from that shown or
discussed, including substantially concurrently or in reverse
order, depending on the functionality involved, as would be
understood by those skilled in the art.
[0198] All of the methods and processes described above may be at
least partially embodied in, and partially or fully automated via,
software code modules executed by one or more computers. For
example, the methods described herein may be performed by the
computing system and/or any other suitable computing device. The
methods may be executed on the computing devices in response to
execution of software instructions or other executable code read
from a tangible computer readable medium. A tangible computer
readable medium is a data storage device that can store data that
is readable by a computer system. Examples of computer readable
mediums include read-only memory, random-access memory, other
volatile or non-volatile memory devices, CD-ROMs, magnetic tape,
flash drives, and optical data storage devices.
[0199] It should be emphasized that many variations and
modifications may be made to the above-described embodiments, the
elements of which are to be understood as being among other
acceptable examples. All such modifications and variations are
intended to be included herein within the scope of this disclosure.
The foregoing description details certain embodiments. It will be
appreciated, however, that no matter how detailed the foregoing
appears in text, the systems and methods can be practiced in many
ways. For example, a feature of one embodiment may be used with a
feature in a different embodiment. As is also stated above, it
should be noted that the use of particular terminology when
describing certain features or aspects of the systems and methods
should not be taken to imply that the terminology is being
re-defined herein to be restricted to including any specific
characteristics of the features or aspects of the systems and
methods with which that terminology is associated.
[0200] Various embodiments of a physiological monitoring device,
methods, and systems are disclosed herein. These various
embodiments may be used alone or in combination, and various
changes to individual features of the embodiments may be altered,
without departing from the scope of the invention. For example, the
order of various method steps may in some instances be changed,
and/or one or more optional features may be added to or eliminated
from a described device. Therefore, the description of the
embodiments provided above should not be interpreted as unduly
limiting the scope of the invention as it is set forth in the
claims.
[0201] Various modifications to the implementations described in
this disclosure may be made, and the generic principles defined
herein may be applied to other implementations without departing
from the spirit or scope of this disclosure. Thus, the scope of the
disclosure is not intended to be limited to the implementations
shown herein, but are to be accorded the widest scope consistent
with this disclosure, the principles and the novel features
disclosed herein.
[0202] Certain features that are described in this specification in
the context of separate embodiments also can be implemented in
combination in a single embodiment. Conversely, various features
that are described in the context of a single embodiment also can
be implemented in multiple embodiments separately or in any
suitable subcombination. Moreover, although features may be
described above as acting in certain combinations and even
initially claimed as such, one or more features from a claimed
combination can in some cases be excised from the combination, and
the claimed combination may be directed to a subcombination or
variation of a subcombination.
[0203] Similarly, while operations are depicted in the drawings in
a particular order, such operations need not be performed in the
particular order shown or in sequential order, or that all
illustrated operations be performed, to achieve desirable results.
Further, the drawings may schematically depict one more example
processes in the form of a flow diagram. However, other operations
that are not depicted can be incorporated in the example processes
that are schematically illustrated. For example, one or more
additional operations can be performed before, after,
simultaneously, or between any of the illustrated operations.
Moreover, the separation of various system components in the
embodiments described above should not be interpreted as requiring
such separation in all embodiments. Additionally, some embodiments
are within the scope of the following claims. In some cases, the
actions recited in the claims can be performed in a different order
and still achieve desirable results.
* * * * *