U.S. patent application number 16/017960 was filed with the patent office on 2018-10-18 for extended wear electrocardiography patch.
The applicant listed for this patent is Bardy Diagnostics, Inc.. Invention is credited to Gust H. Bardy, Jon Mikalson Bishay, Jason Felix.
Application Number | 20180296118 16/017960 |
Document ID | / |
Family ID | 56878006 |
Filed Date | 2018-10-18 |
United States Patent
Application |
20180296118 |
Kind Code |
A1 |
Bishay; Jon Mikalson ; et
al. |
October 18, 2018 |
EXTENDED WEAR ELECTROCARDIOGRAPHY PATCH
Abstract
An extended wear electrocardiography patch is provided. A
flexible backing is formed of an elongated strip of stretchable
material. A circuit is affixed to an outward-facing surface of the
flexible backing and includes a pair of circuit traces each
originating with one of the ends of the elongated strip. A pair of
electrocardiographic electrodes are each electrically coupled to
one of the circuit traces and conductively exposed on a contact
surface of each end of the elongated strip through an opening. When
the flexible backing is at rest, the electrodes are approximately
centered over their respective openings on a patient's skin and
during bending of the flexible backing, the electrodes slide over
at least a portion of the flexible backing while maintaining
electrical contact between the electrodes and the patient's
skin.
Inventors: |
Bishay; Jon Mikalson;
(Seattle, WA) ; Bardy; Gust H.; (Carnation,
WA) ; Felix; Jason; (Vashon Island, WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Bardy Diagnostics, Inc. |
Seattle |
WA |
US |
|
|
Family ID: |
56878006 |
Appl. No.: |
16/017960 |
Filed: |
June 25, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15256189 |
Sep 2, 2016 |
10004415 |
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16017960 |
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14736257 |
Jun 10, 2015 |
9433380 |
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15256189 |
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14080717 |
Nov 14, 2013 |
9545204 |
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14736257 |
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61882403 |
Sep 25, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 5/04325 20130101;
A61B 5/04085 20130101; A61B 2562/164 20130101; A61B 5/14532
20130101; A61B 5/6833 20130101; A61B 5/04087 20130101; A61B 5/02055
20130101; A61B 5/04017 20130101; A61B 5/0464 20130101; A61B 5/7455
20130101; A61B 2560/0214 20130101; A61B 2505/07 20130101; A61B
5/0432 20130101; A61B 2560/0443 20130101; A61B 5/087 20130101; A61B
2560/045 20130101; A61B 5/021 20130101; A61B 5/6823 20130101; A61B
2560/0412 20130101; A61B 5/14551 20130101 |
International
Class: |
A61B 5/0408 20060101
A61B005/0408; A61B 5/00 20060101 A61B005/00; A61B 5/0464 20060101
A61B005/0464; A61B 5/0432 20060101 A61B005/0432 |
Claims
1. An extended wear electrocardiography patch, comprising: a
flexible backing formed of an elongated strip of stretchable
material; a circuit affixed to an outward-facing surface of the
flexible backing and comprising a pair of circuit traces each
originating with one of the ends of the elongated strip; a pair of
electrocardiographic electrodes, each electrode electrically
coupled to one of the circuit traces and conductively exposed on a
contact surface of each end of the elongated strip through an
opening, wherein the electrodes are approximately centered over
their respective openings on a patient's skin when the flexible
backing is at rest and during bending of the flexible backing, the
electrodes slide over at least a portion of the flexible backing
while maintaining electrical contact between the electrodes and the
patient's skin.
2. An electrocardiography patch according to claim 1, further
comprising: hydrocolloid adhesive coating at least a portion of the
contact surface of the flexible backing between the flexible
backing and the patient's skin.
3. An electrocardiography patch according to claim 1, wherein the
flexible backing comprises a porous material.
4. An electrocardiography patch according to claim 3, wherein the
porous material comprises spunlace fabric.
5. An electrocardiography patch according to claim 3, wherein the
porous material reduces an amount of moisture trapped by the
flexible backing.
6. An electrocardiography patch according to claim 1, further
comprising: hydrogel placed in each of the openings of the flexible
backing between the electrode in that opening and the patient's
skin.
7. An electrocardiography patch according to claim 1, further
comprising: a receptacle affixed on one end of the flexible backing
on the outward-facing surface and operable to removably receive a
electrocardiography monitor.
8. An electrocardiography patch according to claim 7, wherein the
receptacle comprises electrode terminals aligned to electrically
interface the pair of circuit traces to the electrocardiography
monitor.
9. An electrocardiography patch according to claim 7, further
comprising: a battery compartment provided in the receptacle and
comprising a pair of battery leads electrically coupleable to a
battery; and the receptacle further comprising power terminals
aligned to electrically interface the pair of battery leads to the
electrocardiography monitor.
10. An electrocardiography patch according to claim 1, further
comprising: one of the electrocardiographic electrodes being
disposed for being adhered to a region overlying the Xiphoid
process on a patient's chest; and an other of the
electrocardiographic electrodes being disposed for being adhered to
the region near the manubrium on the patient's chest oriented
centrally (in the midline) along the sternum upwards from the one
electrocardiographic electrode.
11. An electrocardiography patch according to claim 1, further
comprising: a monitor recorder, comprising: an externally-powered
micro-controller operable to execute under micro programmable
control through firmware that is stored in a program memory unit of
the micro-controller; and an electrocardiographic front end circuit
electrically interfaced to the micro-controller and operable to
sense electrocardiographic signals through the electrodes.
12. An electrocardiography and physiological sensor monitor,
comprising: an electrocardiography patch, comprising: a flexible
backing formed of an elongated strip of stretchable material; a
circuit affixed to an outward-facing surface of the flexible
backing and comprising a pair of circuit traces each originating
with one of the ends of the elongated strip; a pair of
electrocardiographic electrodes, each electrode electrically
coupled to one of the circuit traces and conductively exposed on a
contact surface of each end of the elongated strip through an
opening, wherein the electrodes are approximately centered over
their respective openings on a patient's skin when the
electrocardiography patch is at rest and during bending of the
electrocardiography patch, the electrodes slide over at least a
portion of the flexible backing while maintaining electrical
contact between the electrodes and the patient's skin; and a
monitor recorder, comprising: an externally-powered
micro-controller operable to execute under micro programmable
control through firmware that is stored in a program memory unit of
the micro-controller; and an electrocardiographic front end circuit
electrically interfaced to the micro-controller and operable to
sense electrocardiographic signals through the electrodes provided
on the electrocardiography patch.
13. An electrocardiography and physiological sensor monitor
according to claim 12, further comprising: hydrocolloid adhesive
coating at least a portion of the contact surface of the flexible
backing between the flexible backing and the patient's skin.
14. An electrocardiography and physiological sensor monitor
according to claim 12, wherein the flexible backing comprises a
porous material.
15. An electrocardiography and physiological sensor monitor
according to claim 14, wherein the porous material comprises
spunlace fabric.
16. An electrocardiography and physiological sensor monitor
according to claim 14, wherein the porous material reduces an
amount of moisture trapped by the electrocardiography patch.
17. An electrocardiography and physiological sensor monitor
according to claim 12, further comprising: hydrogel placed in each
of the openings of the flexible backing between the electrode in
that opening and the patient's skin.
18. An electrocardiography and physiological sensor monitor
according to claim 12, further comprising: a receptacle affixed on
one end of the flexible backing on the outward-facing surface and
operable to removably receive the monitor.
19. An electrocardiography and physiological sensor monitor
according to claim 18, wherein the receptacle comprises electrode
terminals aligned to electrically interface the pair of circuit
traces to the electrocardiography monitor.
20. An electrocardiography and physiological sensor monitor
according to claim 18, further comprising: a battery compartment
provided in the receptacle and comprising a pair of battery leads
electrically coupleable to a battery; and the receptacle further
comprising power terminals aligned to electrically interface the
pair of battery leads to the electrocardiography monitor.
21. An electrocardiography and physiological sensor monitor
according to claim 12, further comprising: one of the
electrocardiographic electrodes being disposed for being adhered to
a region overlying the Xiphoid process on a patient's chest; and an
other of the electrocardiographic electrodes being disposed for
being adhered to the region near the manubrium on the patient's
chest oriented centrally (in the midline) along the sternum upwards
from the one electrocardiographic electrode.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This non-provisional patent application is a continuation of
U.S. patent application Ser. No. 15/256,189, filed Sep. 2, 2016,
pending, which is a continuation of U.S. Pat. No. 9,433,380, issued
Sep. 6, 2016, which is a continuation-in-part of U.S. Pat. No.
9,545,204, issued Jan. 17, 2017, and further claims priority under
35 U.S.C. .sctn. 119(e) to U.S. Provisional Patent application,
Ser. No. 61/882,403, filed Sep. 25, 2013, the disclosures of which
are incorporated by reference.
FIELD
[0002] This application relates in general to electrocardiographic
monitoring and, in particular, to an extended wear
electrocardiography patch.
BACKGROUND
[0003] The heart emits electrical signals as a by-product of the
propagation of the action potentials that trigger depolarization of
heart fibers. An electrocardiogram (ECG) measures and records such
electrical potentials to visually depict the electrical activity of
the heart over time. Conventionally, a standardized set format
12-lead configuration is used by an ECG machine to record cardiac
electrical signals from well-established traditional chest
locations. Electrodes at the end of each lead are placed on the
skin over the anterior thoracic region of the patient's body to the
lower right and to the lower left of the sternum, on the left
anterior chest, and on the limbs. Sensed cardiac electrical
activity is represented by PQRSTU waveforms that can be interpreted
post-ECG recordation to derive heart rate and physiology. The
P-wave represents atrial electrical activity. The QRSTU components
represent ventricular electrical activity.
[0004] An ECG is a tool used by physicians to diagnose heart
problems and other potential health concerns. An ECG is a snapshot
of heart function, typically recorded over 12 seconds, that can
help diagnose rate and regularity of heartbeats, effect of drugs or
cardiac devices, including pacemakers and implantable
cardioverter-defibrillators (ICDs), and whether a patient has heart
disease. ECGs are used in-clinic during appointments, and, as a
result, are limited to recording only those heart-related aspects
present at the time of recording. Sporadic conditions that may not
show up during a spot ECG recording require other means to diagnose
them. These disorders include fainting or syncope; rhythm
disorders, such as tachyarrhythmias and bradyarrhythmias; apneic
episodes; and other cardiac and related disorders. Thus, an ECG
only provides a partial picture and can be insufficient for
complete patient diagnosis of many cardiac disorders.
[0005] Diagnostic efficacy can be improved, when appropriate,
through the use of long-term extended ECG monitoring. Recording
sufficient ECG and related physiology over an extended period is
challenging, and often essential to enabling a physician to
identify events of potential concern. A 30-day observation day
period is considered the "gold standard" of ECG monitoring, yet
achieving a 30-day observation day period has proven unworkable
because such ECG monitoring systems are arduous to employ,
cumbersome to the patient, and excessively costly. Ambulatory
monitoring in-clinic is implausible and impracticable.
Nevertheless, if a patient's ECG could be recorded in an ambulatory
setting, thereby allowing the patient to engage in activities of
daily living, the chances of acquiring meaningful information and
capturing an abnormal event while the patient is engaged in normal
activities becomes more likely to be achieved.
[0006] For instance, the long-term wear of ECG electrodes is
complicated by skin irritation and the inability ECG electrodes to
maintain continual skin contact after a day or two. Moreover, time,
dirt, moisture, and other environmental contaminants, as well as
perspiration, skin oil, and dead skin cells from the patient's
body, can get between an ECG electrode, the non-conductive adhesive
used to adhere the ECG electrode, and the skin's surface. All of
these factors adversely affect electrode adhesion and the quality
of cardiac signal recordings. Furthermore, the physical movements
of the patient and their clothing impart various compressional,
tensile, and torsional forces on the contact point of an ECG
electrode, especially over long recording times, and an inflexibly
or rigidly fastened ECG electrode will be prone to becoming
dislodged. Moreover, dislodgment may occur unbeknownst to the
patient, making the ECG recordings worthless. Further, some
patients may have skin that is susceptible to itching or
irritation, and the wearing of ECG electrodes can aggravate such
skin conditions. Thus, a patient may want or need to periodically
remove or replace ECG electrodes during a long-term ECG monitoring
period, whether to replace a dislodged electrode, reestablish
better adhesion, alleviate itching or irritation, allow for
cleansing of the skin, allow for showering and exercise, or for
other purpose. Such replacement or slight alteration in electrode
location actually facilitates the goal of recording the ECG signal
for long periods of time.
[0007] Conventionally, Holter monitors are widely used for
long-term extended ECG monitoring. Typically, they are often used
for only 24-48 hours. A typical Holter monitor is a wearable and
portable version of an ECG that include cables for each electrode
placed on the skin and a separate battery-powered ECG recorder. The
cable and electrode combination (or leads) are placed in the
anterior thoracic region in a manner similar to what is done with
an in-clinic standard ECG machine. The duration of a Holter
monitoring recording depends on the sensing and storage
capabilities of the monitor, as well as battery life. A "looping"
Holter (or event) monitor can operate for a longer period of time
by overwriting older ECG tracings, thence "recycling" storage in
favor of extended operation, yet at the risk of losing event data.
Although capable of extended ECG monitoring, Holter monitors are
cumbersome, expensive and typically only available by medical
prescription, which limits their usability. Further, the skill
required to properly place the electrodes on the patient's chest
hinders or precludes a patient from replacing or removing the
precordial leads and usually involves moving the patient from the
physician office to a specialized center within the hospital or
clinic.
[0008] The ZIO XT Patch and ZIO Event Card devices, manufactured by
iRhythm Tech., Inc., San Francisco, Calif., are wearable stick-on
monitoring devices that are typically worn on the upper left
pectoral region to respectively provide continuous and looping ECG
recording. The location is used to simulate surgically implanted
monitors. Both of these devices are prescription-only and for
single patient use. The ZIO XT Patch device is limited to a 14-day
monitoring period, while the electrodes only of the ZIO Event Card
device can be worn for up to 30 days. The ZIO XT Patch device
combines both electronic recordation components and physical
electrodes into a unitary assembly that adheres to the patient's
skin. The ZIO XT Patch device uses adhesive sufficiently strong to
support the weight of both the monitor and the electrodes over an
extended period of time and to resist disadherance from the
patient's body, albeit at the cost of disallowing removal or
relocation during the monitoring period. The ZIO Event Card device
is a form of downsized Holter monitor with a recorder component
that must be removed temporarily during baths or other activities
that could damage the non-waterproof electronics. Both devices
represent compromises between length of wear and quality of ECG
monitoring, especially with respect to ease of long term use,
female-friendly fit, and quality of atrial (P-wave) signals.
[0009] Therefore, a need remains for an extended wear continuously
recording ECG monitor practicably capable of being worn for a long
period of time capable of recording atrial signals reliably. Such
an ECG monitor would preferably be well-suited for use in women and
in some men where breast anatomy can interfere with ECG signal
quality and long term wear.
[0010] A further need remains for a device capable of recording
signals ideal for arrhythmia discrimination, especially a device
designed for atrial activity recording.
SUMMARY
[0011] Physiological monitoring can be provided through a wearable
monitor that includes two components, a flexible extended wear
electrode patch and a removable reusable monitor recorder. The
wearable monitor sits centrally (in the midline) on the patient's
chest along the sternum oriented top-to-bottom. The placement of
the wearable monitor in a location at the sternal midline (or
immediately to either side of the sternum), with its unique narrow
"hourglass"-like shape, significantly improves the ability of the
wearable monitor to cutaneously sense cardiac electric signals,
particularly the P-wave (or atrial activity) and, to a lesser
extent, the QRS interval signals in the ECG waveforms indicating
ventricular activity. The electrode patch is shaped to fit
comfortably and conformal to the contours of the patient's chest
approximately centered on the sternal midline. To counter the
dislodgment due to compressional and torsional forces, a layer of
non-irritating adhesive, such as hydrocolloid, is provided at least
partially on the underside, or contact, surface of the electrode
patch, but only on the electrode patch's distal and proximal ends.
To counter dislodgment due to tensile and torsional forces, a
strain relief is defined in the electrode patch's flexible circuit
using cutouts partially extending transversely from each opposite
side of the flexible circuit and continuing longitudinally towards
each other to define in `S`-shaped pattern. In a further
embodiment, the electrode patch is made from a type of stretchable
spunlace fabric. To counter patient bending motions and prevent
disadhesion of the electrode patch, the outward-facing aspect of
the backing, to which a (non-stretchable) flexible circuit is
fixedly attached, stretches at a different rate than the backing's
skin-facing aspect, where a skin adhesive removably affixes the
electrode patch to the skin. Each of these components are
distinctive and allow for comfortable and extended wear, especially
by women, where breast mobility would otherwise interfere with
monitor use and comfort.
[0012] One embodiment provides an extended wear electrocardiography
patch. A flexible backing is formed of an elongated strip of
stretchable material. A circuit is affixed to an outward-facing
surface of the flexible backing and includes a pair of circuit
traces each originating with one of the ends of the elongated
strip. A pair of electrocardiographic electrodes are each
electrically coupled to one of the circuit traces and conductively
exposed on a contact surface of each end of the elongated strip
through an opening. When the flexible backing is at rest, the
electrodes are approximately centered over their respective
openings on a patient's skin and during bending of the flexible
backing, the electrodes slide over at least a portion of the
flexible backing while maintaining electrical contact between the
electrodes and the patient's skin.
[0013] A further embodiment provides an extended wear
electrocardiography and physiological sensor monitor. A disposable
extended wear electrode patch includes a flexible backing formed of
an elongated strip of stretchable spunlace material with a narrow
longitudinal midsection tapering evenly inward from both ends of
the elongated strip. A layer of stretchable adhesive is applied on
at least a portion of a contact surface of the flexible backing,
which defines a pair of openings on both ends. A non-stretchable
circuit is axially affixed to an outward-facing surface of the
flexible backing and includes a pair of circuit traces both
originating within one of the ends of the elongated strip. The
flexible backing acts as a buffer between the non-stretchable
circuit and the stretchable adhesive and prevents disadhesion of
the flexible backing during bending. A pair of electrocardiographic
electrodes electrically coupled to each of the circuit traces and
respectively affixed to and conductively exposed on the contact
surface of each end of the elongated strip through each of the
openings. Conductive gel is provided in each of the openings and in
electrical contact with the pair of electrocardiographic electrodes
that shift away from the openings in the flexible backing during
the bending. A non-conductive receptacle is securely adhered on one
of the ends of the flexible backing on the outward-facing surface
and a reusable electrocardiography monitor having a sealed housing
is adapted to be removably secured into the non-conductive
receptacle.
[0014] The monitoring patch is especially suited to the female
anatomy. The narrow longitudinal midsection can fit nicely within
the intermammary cleft of the breasts without inducing discomfort,
whereas conventional patch electrodes are wide and, if adhesed
between the breasts, would cause chafing, irritation, frustration,
and annoyance, leading to low patient compliance.
[0015] The foregoing aspects enhance ECG monitoring performance and
quality facilitating long-term ECG recording, critical to accurate
arrhythmia diagnosis.
[0016] In addition, the foregoing aspects enhance comfort in women
(and certain men), but not irritation of the breasts, by placing
the monitoring patch in the best location possible for optimizing
the recording of cardiac signals from the atrium, another feature
critical to proper arrhythmia diagnosis.
[0017] Still other embodiments will become readily apparent to
those skilled in the art from the following detailed description,
wherein are described embodiments by way of illustrating the best
mode contemplated. As will be realized, other and different
embodiments are possible and the embodiments' several details are
capable of modifications in various obvious respects, all without
departing from their spirit and the scope. Accordingly, the
drawings and detailed description are to be regarded as
illustrative in nature and not as restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIGS. 1 and 2 are diagrams showing, by way of examples, an
extended wear electrocardiography monitor, including an extended
wear electrode patch in accordance with one embodiment,
respectively fitted to the sternal region of a female patient and a
male patient.
[0019] FIG. 3 is a perspective view showing an extended wear
electrode patch in accordance with one embodiment with a monitor
recorder inserted.
[0020] FIG. 4 is a perspective view showing the extended wear
electrode patch of FIG. 3 without a monitor recorder inserted.
[0021] FIG. 5 is a top view showing the flexible circuit of the
extended wear electrode patch of FIG. 3.
[0022] FIG. 6 is a perspective view showing the extended wear
electrode patch in accordance with a further embodiment.
[0023] FIG. 7 is an exploded view showing the component layers of
the electrode patch of FIG. 3.
[0024] FIG. 8 is a bottom plan view of the extended wear electrode
patch of FIG. 3 with liner partially peeled back.
[0025] FIGS. 9 and 10 are diagrams showing, by way of examples, an
extended wear electrocardiography monitor, including an extended
wear spunlace electrode patch, in accordance with a further
embodiment, respectively fitted to the sternal region of a female
patient and a male patient.
[0026] FIG. 11 is a perspective view showing an extended wear
spunlace electrode patch in accordance with a further
embodiment.
[0027] FIGS. 12 and 13 are side cut-away views showing the extended
wear spunlace electrode patch of FIG. 11 respectively in flattened
and inwardly bent aspects.
DETAILED DESCRIPTION
[0028] Physiological monitoring can be provided through a wearable
monitor that includes two components, a flexible extended wear
electrode patch and a removable reusable monitor recorder. FIGS. 1
and 2 are diagrams showing, by way of examples, an extended wear
electrocardiography monitor 12, including an extended wear
electrode patch 15 in accordance with one embodiment, respectively
fitted to the sternal region of a female patient 10 and a male
patient 11. The wearable monitor 12 sits centrally (in the midline)
on the patient's chest along the sternum 13 oriented top-to-bottom
with the monitor recorder 14 preferably situated towards the
patient's head. The electrode patch 15 is shaped to fit comfortably
and conformal to the contours of the patient's chest approximately
centered on the sternal midline 16 (or immediately to either side
of the sternum 13). The distal end of the electrode patch 15
extends towards the Xiphoid process and, depending upon the
patient's build, may straddle the region over the Xiphoid process.
The proximal end of the electrode patch 15, located under the
monitor recorder 14, is below the manubrium and, depending upon
patient's build, may straddle the region over the manubrium.
[0029] To optimize capture of P-wave signals, the electrode patch
15 can advantageously be positioned axially along the midline of a
wearer's sternum 13, such as described in commonly-assigned U.S.
Pat. No. 9,700,227, issued Jul. 11, 2017, the disclosure of which
is incorporated by reference. The placement of the wearable monitor
12 in a location at the sternal midline 16 (or immediately to
either side of the sternum 13) significantly improves the ability
of the wearable monitor 12 to cutaneously sense cardiac electric
signals, particularly the P-wave (or atrial activity) and, to a
lesser extent, the QRS interval signals in the ECG waveforms that
indicate ventricular activity. The sternum 13 overlies the right
atrium of the heart and the placement of the wearable monitor 12 in
the region of the sternal midline 13 puts the ECG electrodes of the
electrode patch 15 in a location better adapted to sensing and
recording P-wave signals than other placement locations, say, the
upper left pectoral region. In addition, placing the lower or
inferior pole (ECG electrode) of the electrode patch 15 over (or
near) the Xiphoid process facilitates sensing of right ventricular
activity and provides superior recordation of the QRS interval.
[0030] During use, the electrode patch 15 is first adhesed to the
skin along the sternal midline 16 (or immediately to either side of
the sternum 13). A monitor recorder 14 is then snapped into place
on the electrode patch 15 to initiate ECG monitoring. FIG. 3 is a
perspective view showing an extended wear electrode patch 15 in
accordance with one embodiment with a monitor recorder 14 inserted.
The body of the electrode patch 15 is preferably constructed using
a flexible backing 20 formed as an elongated strip 21 of wrap knit
or similar stretchable material about 145 mm long and 32 mm at the
widest point with a narrow longitudinal mid-section 23 evenly
tapering inward from both sides. A pair of cut-outs 22 between the
distal and proximal ends of the electrode patch 15 create a narrow
longitudinal midsection 23 or "isthmus" and defines an elongated
"hourglass"-like shape, when viewed from above, such as described
in commonly-assigned U.S. Design Pat. No. D744,659, issued Dec. 1,
2015, the disclosure of which is incorporated by reference. The
upper part of the "hourglass" is sized to allow an electrically
non-conductive receptacle 25, sits on top of the outward-facing
surface of the electrode patch 15, to be affixed to the electrode
patch 15 with an ECG electrode placed underneath on the
patient-facing underside, or contact, surface of the electrode
patch 15; the upper part of the "hourglass" has a longer and wider
profile than the lower part of the "hourglass," which is sized
primarily to allow just the placement of an ECG electrode.
[0031] The electrode patch 15 incorporates features that
significantly improve wearability, performance, and patient comfort
throughout an extended monitoring period. During wear, the
electrode patch 15 is susceptible to pushing, pulling, and
torqueing movements, including compressional and torsional forces
when the patient bends forward, and tensile and torsional forces
when the patient leans backwards. To counter these stress forces,
the electrode patch 15 incorporates crimp and strain reliefs, as
further described infra respectively with reference to FIGS. 4 and
5. In addition, the cut-outs 22 and longitudinal midsection 23 help
minimize interference with and discomfort to breast tissue,
particularly in women (and gynecomastic men). The cut-outs 22 and
longitudinal midsection 23 allow better conformity of the electrode
patch 15 to sternal bowing and to the narrow isthmus of flat skin
that can occur along the bottom of the intermammary cleft between
the breasts, especially in buxom women. The cut-outs 22 and
longitudinal midsection 23 help the electrode patch 15 fit nicely
between a pair of female breasts in the intermammary cleft. In one
embodiment, the cut-outs 22 can be graduated to form the
longitudinal midsection 23 as a narrow in-between stem or isthmus
portion about 7 mm wide. In a still further embodiment, tabs 24 can
respectively extend an additional 8 mm to 12 mm beyond the distal
and proximal ends of the flexible backing 20 to facilitate purchase
when adhering the electrode patch 15 to or removing the electrode
patch 15 from the sternum 13. These tabs preferably lack adhesive
on the underside, or contact, surface of the electrode patch 15.
Still other shapes, cut-outs and conformities to the electrode
patch 15 are possible.
[0032] The monitor recorder 14 removably and reusably snaps into an
electrically non-conductive receptacle 25 during use. The monitor
recorder 14 contains electronic circuitry for recording and storing
the patient's electrocardiography as sensed via a pair of ECG
electrodes provided on the electrode patch 15, such as described in
commonly-assigned U.S. Pat. No. 9,730,593, issued Aug. 15, 2017,
the disclosure of which is incorporated by reference. The circuitry
includes a microcontroller, flash storage, ECG signal processing,
analog-to-digital conversion (where applicable), and an external
interface for coupling to the electrode patch 15 and to an download
station for stored data download and device programming. The
monitor recorder 14 also includes external patient-interfaceable
controls, such as a push button to facilitate event marking and a
resonance circuit to provide vibratory output. In a further
embodiment, the circuitry, with the assistance of the appropriate
types of deployed electrodes or sensors, is capable of monitoring
other types of physiology, in addition to ECGs. Still other types
of monitor recorder components and functionality are possible.
[0033] The non-conductive receptacle 25 is provided on the top
surface of the flexible backing 20 with a retention catch 26 and
tension clip 27 molded into the non-conductive receptacle 25 to
conformably receive and securely hold the monitor recorder 14 in
place. The edges of the bottom surface of the non-conductive
receptacle 25 are preferably rounded, and the monitor recorder 14
is nestled inside the interior of the non-conductive receptacle 25
to present a rounded (gentle) surface, rather than a sharp edge at
the skin-to-device interface.
[0034] The electrode patch 15 is intended to be disposable. The
monitor recorder 14, however, is reusable and can be transferred to
successive electrode patches 15 to ensure continuity of monitoring.
The placement of the wearable monitor 12 in a location at the
sternal midline 16 (or immediately to either side of the sternum
13) benefits long-term extended wear by removing the requirement
that ECG electrodes be continually placed in the same spots on the
skin throughout the monitoring period. Instead, the patient is free
to place an electrode patch 15 anywhere within the general region
of the sternum 13.
[0035] As a result, at any point during ECG monitoring, the
patient's skin is able to recover from the wearing of an electrode
patch 15, which increases patient comfort and satisfaction, while
the monitor recorder 14 ensures ECG monitoring continuity with
minimal effort. A monitor recorder 14 is merely unsnapped from a
worn out electrode patch 15, the worn out electrode patch 15 is
removed from the skin, a new electrode patch 15 is adhered to the
skin, possibly in a new spot immediately adjacent to the earlier
location, and the same monitor recorder 14 is snapped into the new
electrode patch 15 to reinitiate and continue the ECG
monitoring.
[0036] During use, the electrode patch 15 is first adhered to the
skin in the sternal region. FIG. 4 is a perspective view showing
the extended wear electrode patch 15 of FIG. 3 without a monitor
recorder 14 inserted. A flexible circuit 32 is adhered to each end
of the flexible backing 20. A distal circuit trace 33 from the
distal end 30 of the flexible backing 20 and a proximal circuit
trace (not shown) from the proximal end 31 of the flexible backing
20 electrically couple ECG electrodes (not shown) to a pair of
electrical pads 34. The electrical pads 34 are provided within a
moisture-resistant seal 35 formed on the bottom surface of the
non-conductive receptacle 25. When the monitor recorder 14 is
securely received into the non-conductive receptacle 25, that is,
snapped into place, the electrical pads 34 interface to electrical
contacts (not shown) protruding from the bottom surface of the
monitor recorder 14, and the moisture-resistant seal 35 enables the
monitor recorder 14 to be worn at all times, even during bathing or
other activities that could expose the monitor recorder 14 to
moisture.
[0037] In addition, a battery compartment 36 is formed on the
bottom surface of the non-conductive receptacle 25, and a pair of
battery leads (not shown) electrically interface the battery to
another pair of the electrical pads 34. The battery contained
within the battery compartment 35 can be replaceable, rechargeable
or disposable.
[0038] The monitor recorder 14 draws power externally from the
battery provided in the non-conductive receptacle 25, thereby
uniquely obviating the need for the monitor recorder 14 to carry a
dedicated power source. The battery contained within the battery
compartment 35 can be replaceable, rechargeable or disposable. In a
further embodiment, the ECG sensing circuitry of the monitor
recorder 14 can be supplemented with additional sensors, including
an SpO.sub.2 sensor, a blood pressure sensor, a temperature sensor,
respiratory rate sensor, a glucose sensor, an air flow sensor, and
a volumetric pressure sensor, which can be incorporated directly
into the monitor recorder 14 or onto the non-conductive receptacle
25.
[0039] The placement of the flexible backing 20 on the sternal
midline 16 (or immediately to either side of the sternum 13) also
helps to minimize the side-to-side movement of the wearable monitor
12 in the left- and right-handed directions during wear. However,
the wearable monitor 12 is still susceptible to pushing, pulling,
and torqueing movements, including compressional and torsional
forces when the patient bends forward, and tensile and torsional
forces when the patient leans backwards. To counter the dislodgment
of the flexible backing 20 due to compressional and torsional
forces, a layer of non-irritating adhesive, such as hydrocolloid,
is provided at least partially on the underside, or contact,
surface of the flexible backing 20, but only on the distal end 30
and the proximal end 31. As a result, the underside, or contact
surface of the longitudinal midsection 23 does not have an adhesive
layer and remains free to move relative to the skin. Thus, the
longitudinal midsection 23 forms a crimp relief that respectively
facilitates compression and twisting of the flexible backing 20 in
response to compressional and torsional forces. Other forms of
flexible backing crimp reliefs are possible.
[0040] Unlike the flexible backing 20, the flexible circuit 32 is
only able to bend and cannot stretch in a planar direction. FIG. 5
is a top view showing the flexible circuit 32 of the extended wear
electrode patch 15 of FIG. 3. A distal ECG electrode 38 and
proximal ECG electrode 39 are respectively coupled to the distal
and proximal ends of the flexible circuit 32. The flexible circuit
32 preferably does not extend to the outside edges of the flexible
backing 20, thereby avoiding gouging or discomforting the patient's
skin during extended wear, such as when sleeping on the side.
During wear, the ECG electrodes 38, 39 must remain in continual
contact with the skin. A strain relief 40 is defined in the
flexible circuit 32 at a location that is partially underneath the
battery compartment 36 when the flexible circuit 32 is affixed to
the flexible backing 20. The strain relief 40 is laterally
extendable to counter dislodgment of the ECG electrodes 38, 39 due
to tensile and torsional forces. A pair of strain relief cutouts 41
partially extend transversely from each opposite side of the
flexible circuit 32 and continue longitudinally towards each other
to define in `S`-shaped pattern, when viewed from above. The strain
relief respectively facilitates longitudinal extension and twisting
of the flexible circuit 32 in response to tensile and torsional
forces. Other forms of circuit board strain relief are
possible.
[0041] The flexible circuit 32 can be provided either above or
below the flexible backing 20. FIG. 6 is a perspective view showing
the extended wear electrode patch 15 in accordance with a further
embodiment. The flexible circuit (not shown) is provided on the
underside, or contact, surface of the flexible backing 20 and is
electrically interfaced to the set of electrical pads 34 on the
bottom surface of the non-conductive receptacle 25 through
electrical contacts (not shown) pierced through the flexible
backing 20.
[0042] The electrode patch 15 is intended to be a disposable
component, which enables a patient to replace the electrode patch
15 as needed throughout the monitoring period, while maintaining
continuity of physiological sensing through reuse of the same
monitor recorder 14. FIG. 7 is an exploded view showing the
component layers of the electrode patch 15 of FIG. 3. The flexible
backing 20 is constructed of a wearable gauze, latex, or similar
wrap knit or stretchable and wear-safe material 44, such as a
Tricot-type linen with a pressure sensitive adhesive (PSA) on the
underside, or contact, surface. The wearable material 44 is coated
with a layer 43 of non-irritating adhesive, such as hydrocolloid,
to facilitate long-term wear. The hydrocolloid, for instance, is
typically made of mineral oil, cellulose and water and lacks any
chemical solvents, so should cause little itching or irritation.
Moreover, hydrocolloid is thicker and more gel-like than most forms
of PSA and provides cushioning between the relatively rigid and
unyielding non-conductive receptacle 25 and the patient's skin. In
a further embodiment, the layer of non-irritating adhesive can be
contoured, such as by forming the adhesive with a concave or convex
cross-section; surfaced, such as through stripes or crosshatches of
adhesive, or by forming dimples in the adhesive's surface; or
applied discontinuously, such as with a formation of discrete dots
of adhesive.
[0043] As described supra with reference to FIG. 5, a flexible
circuit can be adhered to either the outward facing surface or the
underside, or contact, surface of the flexible backing 20. For
convenience, a flexible circuit 47 is shown relative to the outward
facing surface of the wearable material 44 and is adhered
respectively on a distal end by a distal electrode seal 45 and on a
proximal end by a proximal electrode seal 45. In a further
embodiment, the flexible circuit 47 can be provided on the
underside, or contact, surface of the wearable material 44. Through
the electrode seals, only the distal and proximal ends of the
flexible circuit 47 are attached to the wearable material 44, which
enables the strain relief 40 (shown in FIG. 5) to respectively
longitudinally extend and twist in response to tensile and
torsional forces during wear. Similarly, the layer 43 of
non-irritating adhesive is provided on the underside, or contact,
surface of the wearable material 44 only on the proximal and distal
ends, which enables the longitudinal midsection 23 (shown in FIG.
3) to respectively bow outward and away from the sternum 13 or
twist in response to compressional and torsional forces during
wear.
[0044] A pair of openings 46 is defined on the distal and proximal
ends of the wearable material 44 and layer 43 of non-irritating
adhesive for ECG electrodes 38, 39 (shown in FIG. 5). The openings
46 serve as "gel" wells with a layer of hydrogel 41 being used to
fill the bottom of each opening 46 as a conductive material that
aids electrode signal pick up. The entire underside, or contact,
surface of the flexible backing 20 is protected prior to use by a
liner layer 40 that is peeled away, as shown in FIG. 8.
[0045] The non-conductive receptacle 25 includes a main body 54
that is molded out of polycarbonate, ABS, or an alloy of those two
materials to provide a high surface energy to facilitate adhesion
of an adhesive seal 53. The main body 54 is attached to a battery
printed circuit board 52 by the adhesive seal 53 and, in turn, the
battery printed circuit board 52 is adhesed to the flexible circuit
47 with an upper flexible circuit seal 50. A pair of conductive
transfer adhesive points 51 or, alternatively, metallic rivets or
similar conductive and structurally unifying components, connect
the circuit traces 33, 37 (shown in FIG. 5) of the flexible circuit
47 to the battery printed circuit board 52. The main body 54 has a
retention catch 26 and tension clip 27 (shown in FIG. 3) that
fixably and securely receive a monitor recorder 14 (not shown), and
includes a recess within which to circumferentially receive a die
cut gasket 55, either rubber, urethane foam, or similar suitable
material, to provide a moisture resistant seal to the set of pads
34.
[0046] The strain relief 40 defined in the shape of the flexible
circuit 32 helps counter the pushing, pulling, and torqueing
movements, including compressional and torsional forces, to which
the electrode patch 15 can be subjected during normal wear by
affording a significant degree of free movement along the narrow
longitudinal mid-section 23. Alternatively, an equivalent range of
strain relief can be provided by using a spunlace fabric as the
electrode patch's backing, which can also simply fabrication and
lower manufacturing costs. FIGS. 9 and 10 are diagrams showing, by
way of examples, an extended wear electrocardiography monitor 112,
including an extended wear spunlace electrode patch 115 in
accordance with a further embodiment, respectively fitted to the
sternal region of a female patient 10 and a male patient 11. The
spunlace electrode patch 115 is slightly larger than the
non-spunlace electrode patch 15 (shown in FIG. 1 et seq.) by
approximately ten to fifteen percent. As before, the wearable
monitor 112 sits centrally (in the midline) on the patient's chest
along the sternum 13 oriented top-to-bottom with the monitor
recorder 14 preferably situated towards the patient's head. The
spunlace electrode patch 115 is also shaped to fit comfortably and
conformal to the contours of the patient's chest approximately
centered on the sternal midline 16 (or immediately to either side
of the sternum 13). The distal end of the electrode patch 115
extends towards the Xiphoid process and, depending upon the
patient's build, may straddle the region over the Xiphoid process.
The proximal end of the electrode patch 115, located under the
monitor recorder 14, is below the manubrium and, depending upon
patient's build, may straddle the region over the manubrium.
[0047] Without some form of strain relief, the extended wear
electrocardiography monitor 112 can possibly partially or
completely disadhere during wear. The backing material used in the
spunlace electrode patch 115 provides relief from strain that would
otherwise cause the patch to pull loose from the skin when the
patient twists, turns, or moves about. FIG. 11 is a perspective
view showing an extended wear spunlace electrode patch 115 in
accordance with a further embodiment. The backing 116 of the
spunlace electrode patch 115 is a type of stretchable spunlace
fabric, such as white spunlace polyester nonwoven medical tape 1776
or tan spunlace polyester nonwoven medical tape 9916, both
manufactured by The 3M Company, St. Paul, Minn. Other forms of
fabrics or materials that allow different rates of stretch on
contact (skin-facing) and outward-facing surfaces are possible. A
flexible circuit 117 is fixedly adhered to the outward-facing
aspect of the backing 116 and a circuit trace 118 formed on the
flexible circuit 117 connects a distal electrode (not shown)
disposed on the skin-facing aspect of the backing 116 to the
electrical pads of the non-conductive receptacle 25 (shown in FIG.
4).
[0048] The flexible circuit 117 can flex and bend, but is not
generally able to stretch by an appreciable margin, if at all.
However, the stretchable spunlace fabric used in the backing 116 of
the spunlace electrode patch 115 can compensate for the inability
of the flexible circuit 117 to stretch by enabling the backing 116
to stretch at different rates along the patch's skin-facing and
outward-facing aspects. FIGS. 12 and 13 are side cut-away views
showing the extended wear spunlace electrode patch of FIG. 11
respectively in flattened and inwardly bent aspects. Referring
first to FIG. 12, when at rest, the spunlace electrode patch 115
has a flattened appearance when viewed from the side. The
skin-facing surface of the backing 116 is coated with a form of
hydrocolloid patient skin adhesive 119. The hydrocolloid patient
skin adhesive 119 can be applied on the entire skin-facing surface
of the backing 116 or just on each end of the patch. A distal
electrode 120 and a proximal electrode 122 are electrically coupled
and fixedly attached to the flexible circuit 117 and disposed
towards the skin through a pair of openings in the backing 116.
Semi-viscous hydrogel 121 and 123 are provided in each of the
openings; the semi-viscous hydrogel 121 and 123 serve as conductive
interfaces between each respective electrode 120 and 122 and the
skin's surface.
[0049] When the spunlace electrode patch 115 is at rest, the
electrodes 120 and 122 are approximately centered over their
respective openings in the backing 116. Referring next to FIG. 13,
when the patient bends, stretches, or moves about, the spunlace
electrode patch 115 can deflect away from the flattened aspect. The
flexible circuit 117 and the electrodes 120 and 122 form a
relatively unitary structure that is not able to stretch.
Consequently, when the spunlace electrode patch 115 bends, the
electrodes 120 and 122 will naturally shift away 124 from their
respective openings, although the semi-viscous hydrogel 121 and 123
ensures that electrical contact between the electrodes 120 and 122
and the skin's surface is maintained. To counter the bending motion
and prevent disadhesion of the spunlace electrode patch 115, the
outward-facing aspect of the backing 116, to which the
non-stretchable flexible circuit 117 is fixedly attached, stretches
at a different rate than the backing's skin-facing aspect, where
the hydrocolloid patient skin adhesive 119 removably affixes the
spunlace electrode patch 115 to the skin. The spunlace electrode
patch 115 thus remains attached to the skin with the spunlace
fabric acting as an intermediary or buffer between the
(non-stretchable) flexible circuit 117 and the (stretchable)
hydrocolloid patient skin adhesive 119.
[0050] In addition to providing a strain relief to the spunlace
electrode patch 115, the spunlace fabric offers other advantages.
First, the spunlace fabric is more porous than the types of
standard polyester film or foam material that is often used in
adhesive patches. Spunlace fabric's porosity allows sweat to be
transmitted from the skin to the outside of the patch, which
increases patient comfort, decreases itching and irritation, and
the reduction in trapped moisture extends the effective life of the
adhesive. Second, spunlace fabric has softer edges, which also
increases patient comfort during twisting and turning when compared
to more rigid materials, such as polyester or polyethylene foam, or
polyester film backings.
[0051] While the invention has been particularly shown and
described as referenced to the embodiments thereof, those skilled
in the art will understand that the foregoing and other changes in
form and detail may be made therein without departing from the
spirit and scope.
* * * * *