U.S. patent application number 11/264328 was filed with the patent office on 2006-07-13 for hemodynamic assessment/adjustment.
Invention is credited to Patricia A. Arand, Peter T. Bauer, Robert A. Warner.
Application Number | 20060155202 11/264328 |
Document ID | / |
Family ID | 36654174 |
Filed Date | 2006-07-13 |
United States Patent
Application |
20060155202 |
Kind Code |
A1 |
Arand; Patricia A. ; et
al. |
July 13, 2006 |
Hemodynamic assessment/adjustment
Abstract
A method and system for gathering, creating and utilizing
signal-processed ECG and acoustic signals for assessing, via
presenting a highly intuitive, multi-component, common-time-base,
real-time output display of selected (1) timing, (2) relative
timing, and (3) other significant heart-behavioral elements
relevant to such an assessment, both a non-pacemaker patient's, and
a pacemaker patient's, hemodynamic condition. The method and system
offer an important option and capability for automatic, and/or
manual, medical-treatment and/or pacemaker-control feedback, in
real time, to improve a patient's hemodynamic status, with such a
patient's resulting hemodynamic-behavioral/status changes caused by
such feedback being viewable immediately in the invention's
produced output display,
Inventors: |
Arand; Patricia A.;
(McMinnville, OR) ; Bauer; Peter T.; (West Linn,
OR) ; Warner; Robert A.; (Tigard, OR) |
Correspondence
Address: |
ROBERT D. VARITZ, P.C.
4915 SE 33RD PLACE
PORTLAND
OR
97202
US
|
Family ID: |
36654174 |
Appl. No.: |
11/264328 |
Filed: |
November 1, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60644501 |
Jan 12, 2005 |
|
|
|
Current U.S.
Class: |
600/513 ;
600/528 |
Current CPC
Class: |
A61B 7/00 20130101; A61B
5/742 20130101; A61B 5/7217 20130101; A61N 1/3702 20130101; A61B
7/04 20130101; A61B 5/318 20210101 |
Class at
Publication: |
600/513 ;
600/528 |
International
Class: |
A61B 5/0402 20060101
A61B005/0402 |
Claims
1. A method utilizing signal-processed ECG-electrical and
heart-sound acoustic signal information for assessing a patient's
hemodynamic condition comprising collecting, over a selected time
span, for transmission for hemodynamic-condition signal processing,
simultaneous ECG-electrical and heart-sound acoustic signals, and
based on said processing, producing a comprehensive time-based
display including (a) ECG and acoustic waveforms, and (b) geometric
graphical indicia generally keyed to these waveforms, whereby the
produced-display waveforms and graphical indicia collectively
present a visual description of the patient's hemodynamic
condition.
2. The method of claim 1, wherein said producing of geometric
graphical indicia includes establishing an intuitive heart-sound
marker display designating the time locations of at least one of
heart sounds S.sub.1, S.sub.2, S.sub.3 and S.sub.4.
3. The method of claim 2, wherein said establishing of an intuitive
heart-sound marker display includes placing therein (a)
systolically-associated sound markers which are presented above a
neutral axis line, and (b) diastolically-associated sound markers
which are displayed below the same neutral axis line.
4. The method of claim 3, wherein said producing of a display
presenting hemodynamic condition information involves including in
that display elements relating to (a) electromechanical activation
time, (b) LV systolic time, (c) pre-atrial diastolic time, and (d)
accelerated atrial filling time.
5. The method of claim 1, wherein said producing of a display
presenting hemodynamic condition information involves including in
that display elements relating to (a) electromechanical activation
time, (b) LV systolic time, (c) pre-atrial diastolic time, and (d)
accelerated atrial filling time.
6. The method of claim 1 which further comprises utilizing
collected ECG-electrical and heart-sound acoustic signals in a
feedback manner to effect changes in the operation of the patient's
medical treatment in a fashion aimed at improving the patient's
hemodynamic status.
7. A method utilizing signal-processed ECG and heart-sound signal
information for assessing a pacemaker patient's hemodynamic
condition comprising collecting, over a selected time span, for
transmission for hemodynamic-condition signal processing,
simultaneous ECG-electrical and heart-sound acoustic signals, while
so collecting, detecting, electrically, pacemaker-induced
ventricular stimulation, and on detecting such stimulation,
creating and applying a selected blanking time which effectively
prevents hemodynamic-condition signal-processing of acoustic
signals that are collected during that blanking time.
8. The method of claim 7 which further comprises generating,
substantially simultaneously with respect to the beginning of the
created and applied blanking time, an acoustic window which permits
examining, during that window, of any collected and thus windowed
acoustic signal to determine whether it represents an acoustic
artifact produced by pacemaker-induced phrenic nerve
stimulation.
9. The method of claim 8 which further comprises selectively using
the determination of the presence of phrenic nerve stimulation to
modify the operation of the patient's pacemaker.
10. The method of claim 7 which further comprises, in relation to
application of a blanking time, producing a time-based graphical
display containing indicia which are visually descriptive of
selective components of the patient's hemodynamic condition.
11. The method of claim 10, wherein said producing includes
establishing (a) an ECG-signal display component, (b) a heart-sound
acoustic signal display component, and (c) an intuitive,
heart-sound marker display component designating the time locations
of at least one of heart sounds S.sub.1, S.sub.2, S.sub.3 and
S.sub.4.
12. The method of claim 11, wherein said establishing of an
intuitive heart-sound marker display includes placing therein (a)
systolically-associated sound markers which are presented above a
neutral axis line, and (b) diastolically-associated sound markers
which are displayed below the same neutral axis line.
13. The method of claim 12, wherein said producing of a display
presenting hemodynamic condition information involves including in
that display elements relating to (a) electromechanical activation
time, (b) LV systolic time, (c) pre-atrial diastolic time, and (d)
accelerated atrial filling time.
14. The method of claim 7 which further comprises utilizing
collected ECG-electrical and heart-sound acoustic signals in a
feedback manner to effect changes in the operation of the patient's
pacemaker in a fashion aimed at improving the patient's hemodynamic
status.
15. A system for assessing a patient's hemodynamic condition
comprising sensor structure for collecting, over a selected time
span, for hemodynamic-condition signal-processing, simultaneous
ECG-electrical and heart-sound acoustic signals, signal-processing
structure operatively connected to said sensor structure for
receiving therefrom and processing such collected ECG-electrical
and heart-sound acoustic signals, and display structure operatively
connected to said signal-processing structure for producing, based
on processing performed by said signal-processing structure, a
comprehensive time-based display including (a) ECG and acoustic
waveforms, and (b) geometric graphical indicia generally keyed to
these waveforms, whereby the produced-display waveforms and
graphical indicia collectively present a visual description of the
patient's hemodynamic condition.
16. The system of claim 15, wherein said display structure, in
relation to production of the time-based display of geometric
graphical indicia, includes, in that indicia, display elements
relating to (a) electromechanical activation time, (b) LV systolic
time, (c) pre-atrial diastolic time, and (d) accelerated atrial
filling time
17. A system for assessing a pacemaker patient's hemodynamic
condition comprising sensor structure for collecting, over a
selected time span, for hemodynamic-condition signal-processing,
simultaneous ECG-electrical and heart-sound acoustic signals,
signal-processing structure operatively connected to said sensor
structure for receiving therefrom and processing such collected
ECG-electrical and heart-sound acoustic signals, detecting
structure operatively connected to said sensor structure and to
said signal-processing structure for detecting, electrically,
pacemaker-induced ventricular stimulation, and on detecting such
stimulation, for creating and applying a selected blanking time
which effectively prevents hemodynamic-condition signal-processing
by said signal-processing structure of acoustic signals that are
collected during that blanking time, and display structure
operatively connected to said signal-processing structure for
producing, based on processing performed by said signal-processing
structure, and in relation to the creation and application of such
a blanking time, a time-based graphical display containing indicia
which are visually descriptive of selected components of the
patient's hemodynamic condition.
18. The system of claim 17, wherein said display structure is
constructed to produce such a display which includes (a) ECG and
acoustic waveforms, and (b) geometric graphical indicia generally
keyed to these waveforms, whereby the included ECG and acoustic
waveforms, and the geometric graphical indicia, collectively
present a visual description of the patient's hemodynamic
condition.
19. The system of claim 18, wherein the geometric graphical indicia
includes elements relating to (a) electromechanical activation
time, (b) LV systolic time, (c) pre-atrial diastolic time, and (d)
accelerated atrial filling time.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to the filing date of U.S.
Provisional Patent Application Ser. No. 60/644,501 filed Jan. 12,
2005 for "Methodology and Apparatus for Cooperative, Interrelated
ECG-Sound and Pacemaker Heart-Activity, and Associated Signal,
Interaction". The entire disclosure content of that prior-filed
provisional application is hereby incorporated herein by
reference.
BACKGROUND AND SUMMARY OF THE INVENTION
[0002] This invention pertains to a certain aspect of cardiology,
and in particular, to methodology and associated system apparatus
that are employable with respect to both pacemaker and
non-pacemaker patients to obtain useful heart-sound and
ECG-electrical information which enables a very accurate, and
graphically intuitive, assessment of a patient's hemodynamic
status. The invention also provides an important feedback
opportunity for adjusting a patient's current medical treatment,
including the making of a pacemaker operational adjustment in the
case of a pacemaker patient, in a manner aimed at improving that
patient's hemodynamic condition. With the system and methodology of
the invention in operation, the results of such feedback can be
viewed immediately in real time.
[0003] The invention thus addresses an important area of cardiology
wherein it is considered to be very useful and important to be
able, under real-time, result-observation conditions, to fine-tune
a person's hemodynamic behavior and condition. Preferred
implementation of the invention, while relevant to all categories
of patients, is particularly described herein, in the interest of
giving a full illustration of the invention, in the context of a
pacemaker patient, with the understanding that practice of the
invention for a non-pacemaker patient is similar, save those
descriptive details herein which especially focus on pacemaker
behavior, per se. The terms "pacemaker" and "pacemaker patient" are
employed herein to include situations involving patients and
implant equipment relating to cardiac resynchronization
therapy.
[0004] In this context, it is now very well recognized that, in
addition to the heart-condition-assessment value of possessing
accurately gathered and clearly readable ECG electrical
information, is also extremely valuable to obtain, for accurate
viewing, simultaneously occurring heart-sound information relating
especially to the heart sounds known as the S.sub.1, S.sub.2,
S.sub.3 and S.sub.4 heart sounds. As those skilled in the art
recognize, there are various kinds of conditions which can make
difficult the accurate acquisition and identification of clearly
confirmable heart sounds, often because of various "other
conditions" which tend to obscure accurate heart-sound information.
One of these troublesome, "obscuring" conditions exhibits itself
sometimes in the presence of pacemaker operation in the form of
phrenic nerve stimulation. More specifically, too vigorous a
pacemaker ventricular pacing pulse, an issue in and of itself, can
produce such stimulation which, in turn generates an acoustic
artifact that can "confuse" a heart-sound diagnostic algorithm in a
way which mars accurate heart-sound investigation.
[0005] The present invention, in the context of improving
heart-sound collection and display for hemodynamic status
assessment and adjustment in the realm of pacemaker operation,
takes particular aim at this circumstance and these issues--namely,
at the above-mentioned, unwanted events involving a subject whose
heart has been equipped with a pacemaker. It does so, as will be
seen, with unique methodology which leads to very accurate and
reliable gathering and intuitive presentation of both
ECG-electrical and heart-sound acoustic information, with
appropriate processing being applied to the gathered information to
assure a high level of certainty regarding acquired audio data
containing heart-sound information in categories that are important
to the assessment and management of a subject's hemodynamic
condition. This presentation capability of the invention is, of
course, offered whether or not a pacemaker is involved.
[0006] Describing features of the invention in a "pacemaker"
setting--a very useful way to appreciate the invention's
contributions to the medical diagnostic and treatment arts--the
present invention is structurable to recognize potential "phrenic
nerve stimulation" problems, and when so structured, provides
signal-collection and signal-processing circuitry which responds to
real time pacemaker operation in a manner that effectively (a)
prevents the mentioned heart-sound confusion issue from surfacing,
(b) informs a physician, clinician, etc. that a pacemaker's
ventricular pacing pulse may need to be adjusted, and (c) opens a
significant door for the improved gathering and processing
accuracy, and the presentation, of heart-sound information leading
to accurate assessment (indeed "picturing") of a subject's
hemodynamic condition.
[0007] Additionally, the invention addresses the utility of
employing such carefully gathered and processed information in a
manner enabling feedback control to be applied to an operating
pacemaker so as to enable the physician, or other party, (working
with a particular pacemaker subject) to fine-tune the interrelated
operations of the subject's heart and the associated pacemaker so
as to improve that subject's hemodynamic condition.
[0008] Medical treatment feedback, other than that relating to
pacemaker operation, is also encouraged, promoted, and made
available, based on operation of the invention, for improving, and
for observing feedback results in real time regarding, a patient's
hemodynamic condition.
[0009] The invention further features a unique, visual, graphical
presentation (with geometric elements) of gathered ECG-electrical
and heart-sound acoustic information, in a real time manner, and in
such as fashion that the employment of feedback to control various
medical treatment and/or pacemaker operations so as to improve
hemodynamic behavior can be seen immediately on a very intuitive
visual representation of the associated subject's actual,
then-existent, hemodynamic condition and behavior.
[0010] These and various other features and advantages which are
offered by the present invention will become more fully apparent as
the description which now follows is read in conjunction with the
accompanying drawings.
DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 provides a graphical illustration, well known to
those skilled in the art, of a parameter legended illustration of
the various basic events of the usual left heart cardiac cycle.
This figure specifically carries labels of certain time intervals
which are referenced in relation to what is shown in FIG. 6.
[0012] FIG. 2 is a block/schematic diagram labeled to illustrate
detection of pacemaker-triggered phrenic nerve stimulation, and the
creation of a special sound-information blanking window to
eliminate unwanted and confusion-prone processing of any acoustic
artifact created by such stimulation.
[0013] FIG. 3 provides a graphical illustration which relates to
the operation of what is shown in FIG. 2.
[0014] FIGS. 4 and 5 provide two different high-level
block/schematic diagrams illustrating pacemaker control-feedback to
improve subject hemodynamic status in accordance with practice of
certain features of the present invention. As will be explained
below, FIG. 4, in a slightly modified form which will be described,
can be viewed as illustrating practice of the invention with
non-pacemaker patients.
[0015] FIG. 6 is a multi-component graphic illustration derived
from information gathered in accordance with practice of the
present invention to furnish an intuitive display, over a period of
time including about one-dozen cardiac cycles, of a particular
patient's (subject's) hemodynamic status. This figure, which has
been prepared to show display output operation of the invention for
all categories of relevant patients, including pacemaker patients,
specifically shows, among other things, an effect of pacemaker
feedback control.
[0016] FIG. 7 is a high-level, block/schematic diagram which can be
viewed as illustrating both the overall methodology and the overall
systemic and apparatus nature, of the present invention. This
drawing can be read to cover operation of the invention regarding
both pacemaker and non-pacemaker patients.
DETAILED DESCRIPTION OF THE INVENTION
[0017] Turning now to the drawings, and referring first of all to
FIG. 1, indicated generally at 10 is a relatively well known and
conventional illustration of the events, and of certain measures of
events, of a typical, single cardiac cycle with respect to the left
side of the heart, referred to for simplicity purposes simply as
the left heart. These events are those which normally take place,
and are expected to take place, during such a cardiac cycle. At the
lower portion of each of these two figures, certain timing
intervals that are relevant in different ways to the practice of
the present invention are specifically labeled by different
clusters of capital letters. Set forth immediately below is a
listing of the meanings of these letter labels:
[0018] AAFT--Accelerated Atrial Filling Time
[0019] DT--Diastolic Time
[0020] EMAT--Electromechanical Activation Time
[0021] LVST--LV Systolic Time
[0022] PADT--Pre-Atrial Diastolic Time
[0023] QQ(RR)--Interval between beats
[0024] Still with reference to FIG. 1, this figure specifically
shows a simple parameter model based on ECG/Sound timing intervals.
These intervals are close approximations to hemodynamically
relevant aspects of the cardiac cycle which can be extracted from
echo, cardiac cath, ECG, and heart-sound measurements.
[0025] Looking at, and identifying, the graphical, time-based
traces which appear on the left side of FIG. 1: [0026] 1. Top trace
(12): ECG signal with makers for the p-wave (atrial
depolarization), QRS complex (ventricular depolarization), and
T-wave (ventricular re-polarization). [0027] 2. 2nd trace from top
(14): Pressure tracings (obtainable through catheter measurements).
Shown are the pressure curves for the left ventricle, the left
atrium, and the aorta. [0028] 3. 3rd trace from top (16): Flow
tracings (obtainable through echo tissue Doppler imaging (TDI)).
When the pressure in the left ventricle is higher than in the
aorta, blood is flowing into the aorta (happens between the S1 and
S2 heart sounds)=aortic outflow; while the ventricular pressure is
below the left atrial pressure, the left ventricle get filled with
blood=mitral inflow. The mitral inflow occurs in three phases: a)
passive filling (first hump between the S2 and the next S1)=Echo
TDI E wave, b) diastasis (LA=LV pressure, small hump in the middle,
hardly visible in Echo TDI), and c) active filling (atrial kick)
while the left atrium contracts (hump just before the S1)=Echo TDI
A-wave. [0029] 4. 4th trace from top (18): Heart sound trace
showing an S1 (closure of mitral valve) and S2 (closure of aortic
valve). The third heard sound is not shown, but it would occur
toward the end of the E-wave in the flow trace. [0030] 5. 5th trace
from top (20): Volume trace showing the changes in left ventricular
volume from its minimum=ESV (end systolic volume, so the volume at
the end of ventricular contraction) and its maximum=EDV (end
diastolic volume, so the volume at the end of the ventricular
filling phase).
[0031] As will be seen, it is the several specifically
letter-labeled time periods appearing at the bottom of FIG. 1 which
become employed in the intuitive output display which is shown in
FIG. 6.
[0032] According to practice of the present invention, and in any
suitable manner, during a common span of time, such as a time space
which encompasses about a dozen successive cardiac cycles,
simultaneous ECG-electrical and heart-sound acoustic signals are
collected from anatomical contact sensors applied to the anatomy of
a pacemaker patient, with that patient's, or subject's, pacemaker
in full operation during this time interval.
[0033] In this setting, and as was generally mentioned above, one
aspect of the present invention involves the capability of the
methodology and system of the present invention accurately to
obtain very useful ECG-electrical and heart-sound acoustic signals,
with the latter basically "freed" from being "processed-confused"
by any potentially troublesome pacemaker-induced acoustical
artifact, such as a pacemaker-induced phrenic-nerve-stimulation
artifact.
[0034] Another aspect of the invention involves, in relation to
ECG-electrical and heart-sound acoustic data which is so gathered,
and which is handled in a manner that avoids artifact disturbance,
using that data in a feedback-loop manner to control various
things, such as current medical treatment, and where a pacemaker is
involved, various operating parameters and conditions of a
subject's pacemaker, so as to improve the associated subject's
hemodynamic status, and to do so in a fashion which can be observed
immediately in real time as feedback information is employed, and
as ECG-electrical and heart-sound acoustic signals continue to be
simultaneously gathered and observed.
[0035] Still a further feature and aspect of the present invention
involves the graphical presentation, as output information which is
displayable on a screen, or on a printed strip chart, etc., in a
manner which intuitively and quickly describes to a skilled
observer various pieces of information which lead to an
understanding of the relevant subject's hemodynamic condition.
[0036] Turning attention next to FIGS. 2 and 3 in the drawings,
these two figures effectively illustrate that aspect of the present
invention which relates to handling the issue of pacemaker-induced
phrenic nerve stimulation. To those who are skilled in the relevant
art, FIGS. 2 and 3, taken along with the related descriptive text
which now follows, will fully explain the two special ways in which
the present invention deals with such stimulation.
[0037] FIG. 2 includes seven blocks 22, 24, 26, 28, 30, 32, 34
which are interconnected functionally as shown by obvious
interconnection lines. These blocks are labeled to indicate
generally the function which they perform.
[0038] Block 22 represents both system apparatus and methodology
involved in collecting various electrically discernable biologic
signal information, such as pacemaker timing and other information,
which may be utilized directly or indirectly in the practice of
this invention, either in cooperative addition to, or in some
selectable ancillary manner with respect to, the gathering of
heart-produced ECG-electrical signals and heart-sound acoustic
signals which are sensed and collected, respectively, by blocks 24,
26. For example, certain pacemaker electrical activity, now to be
discussed, may be collected for use in the practice of the present
invention, either by block 22 or by block 24. Blocks 22, 24, 26
collect their respective, associated signals from any suitable
anatomical locations on a subject's body, with ECG-electrical
signal information gathered from a classically recognizable
anatomical site, such as the Lead II ECG anatomical site (as is
represented in FIG. 3), and sound or acoustic information gathered
from another recognized anatomical site, such as the V3 anatomical
site (also represented in FIG. 3). These two, recognized anatomical
sites are proximate one another, and, accordingly, ECG-electrical,
and heart-sound acoustic signals may preferably be acquired
essentially from the same, common site, and along a substantially
common signal-collection axis.
[0039] Signals collected by blocks 22, 24, 26 are passed, in
various ways to be explained, to signal-processing block 34,
wherein one or more appropriate processing and diagnostic
algorithms operate to create, ultimately, from acquired signal
information, the useful output display information which is
produced in accordance with practice of the present invention.
Signals from these three blocks effectively pass "through" block
28, which performs pacemaker event detection functions that will be
explained shortly, out of which block 28, acoustic signals,
effectively en route to signal-processing block 34, are "sent" to
that block either through a route including block 30, with respect
to which a special acoustic blanking window is utilized in
accordance with practice of the invention, or through block 32
wherein specific acoustic detection of phrenic nerve stimulation is
detected, as will shortly be explained.
[0040] Those skilled in the relevant art will fully understand that
there are various different ways in which the specific operations
represented blocks 22-34, inclusive, can be performed, and that,
therefore, various specific signal-handling circuitry approaches,
which may be entirely conventional in internal construction, may
also be used. Accordingly, no specific details of the inner
workings of these blocks are provided herein, inasmuch as they form
no part of the present invention.
[0041] With respect to the operation of the present invention,
electrical and acoustic signals which are gathered and handled in
the fashion illustrated in FIG. 2 are collected in such a fashion
as to focus upon ECG-electrical signals and heart-sound acoustic
signals which can be processed for diagnostic purposes in a manner
which does not allow the desired heart-sound acoustic signals to
become confusingly treated by virtue of any phrenic nerve
stimulation acoustic artifact that may be generated by operation of
a subject's pacemaker. With specific reference to illustrative
natures of signals that are collected and passed along essentially
by blocks 24, 26 in FIG. 2, an ECG-electrical signal from Lead site
II, collected by block 24, is shown generally at 36 in FIG. 3.
Superimposed on this ECG-electrical signal, by virtue of the
ongoing operation of a subject's pacemaker, are the usual atrial
and ventricular electrical pacing pulses which are produced by the
associated pacemaker, with atrial pulses Ap being shown generally
at 38 in FIG. 3, and ventricular pacing pulses Vp being shown
generally at 40 in FIG. 3.
[0042] An acoustic signal gathered by a block 26 in FIG. 2 is shown
generally at 42 in FIG. 3, with there being superimposed on this
acoustic signal an acoustic artifact 44 which results from the fact
that ventricular pacing pulses 40 are energetic enough to be
causing phrenic nerve stimulation.
[0043] It is with respect to the operation of block 28 in FIG. 2
that pacemaker events, such as ventricular pacing pulses 40 are
detected to initiate certain important operations that are
performed in the practice of the present invention.
[0044] According to one preferred practice of the present
invention, under circumstances with a pacemaker operating with
respect to a pacemaker patient, and with the appropriate ones of
block 22, 24, 26 noting and capturing ECG-electrical signals,
pacemaker atrial and ventricular pacing pulse electrical signals,
and acoustic signals including heart-sound acoustic signals, and in
accordance with the intended operations of blocks 30, 32, on the
occurrence of a ventricular pacing pulse 40, and in order to
prevent the possibility of any phrenic nerve stimulation artifact
triggered by that pulse becoming involved in the algorithmic
signal-processing activity relating to discerning and correctly
identifying heart-sound acoustical signals, block 30 creates what
is referred to herein as a blanking time, or a blanking window,
which begins at the onset of each pulse 40. These blanking times,
or windows, are illustrated in FIG. 3 by the solid, darkened blocks
which are shown at 46 in FIG. 3. While different specific time
durations may be selected for establishing the length of each of
these blanking windows, we have found that a blanking window which
has a duration of about 30- to about 40-milliseconds is quite
appropriate. These blanking windows prevent any acoustic-signal
information from being furnished to signal-processing block 34 in a
manner which would cause that information to become confused with
anatomical acoustic signals which are intended to be gathered for
the purpose of interpreting the presence of various heart sounds.
In other words, this automatically triggered blanking window,
triggered by the onset of a pacemaker's ventricular pacing pulse,
prevents the likelihood that any phrenic nerve stimulation which
produces an acoustic artifact will result in that artifact being
confused by the signal-processing circuitry in block 34 with true
heart-sound information.
[0045] As was mentioned, ventricular pacing pulses 40 as seen in
FIG. 3 are energetic enough to be producing phrenic nerve
stimulation at a level which produces related acoustic artifacts
44, and it is these artifacts which are blocked by the blanking
time window from becoming confused with real heart-sound acoustical
signals.
[0046] It is, however, important, and it is accommodated by
operation of the present invention, that the event of phrenic nerve
stimulation be made observable in some fashion to the physician, or
clinician, etc., who is working with a patient whose data is being
gathered, in order to determine whether the operation of the
patient's pacemaker needs to be "toned down" to avoid such
stimulation. Accordingly, a sound artifact 44, which is produced as
illustrated in FIG. 3 by phrenic nerve stimulation triggered by
pacemaker operation, is provided a special time window, i.e., it is
"windowed" as illustrated by the darkened rectangles shown in FIG.
3 at 48. This windowing operation, furnished in accordance with the
operation of block 32 in FIG. 2, provides information to the
associated physician, clinician, etc., from which that person can
determine whether or not an adjustment, in a feedback sense,
manually or automatically provided, needs to be made in the
operation of the pacemaker. The duration of each window 48 herein
is about 30- to about 60-milliseconds.
[0047] Thus, insofar as the operation of the present invention is
concerned with regard to pacemaker patients, pacemaker ventricular
pacing pulses trigger two kinds of windows, or intervals, one of
which performs a blanking function to prevent any resulting sound
artifacts derived from phrenic nerve stimulation from becoming
confused in the analysis provided and produced for heart sounds,
while at the same time permitting any acoustic artifact which
results from phrenic nerve stimulation to be noted so as to allow
for immediate corrective adjustment, if necessary, of the pacing
energy output by the associated pacemaker.
[0048] Control over pacemaker pulsing operation based upon
observation of phrenic-nerve-stimulation-produced acoustic
artifacts may, as suggested immediately above, preferably be
performed by an attending clinician or physician, etc. but may also
be handled in a computer-controlled automatic fashion, if so
desired. Any such adjustment will, of course, become immediately
"readable" with respect to its effect, as along as electrical and
acoustic information continues to be gathered from the relevant
subject.
[0049] Turning attention now to FIGS. 4 and 5 in the drawings, here
are provided two different block/schematic diagrams showing the
methodology of the invention implemented in two, slightly different
manners, all in accordance with practice of the present invention,
especially in the context of a pacemaker patient. These two drawing
figures are seen to include visual representations of certain ones
of the operational blocks which are also shown in, and described
with respect to, FIG. 2. It will be soon be understood that the
respective operations of the not-specifically-shown blocks (28. 30,
32) are carried out "within the confines" of certain other blocks
which are specifically pictured in FIGS. 4 and 5.
[0050] FIG. 4, in addition to including blocks 22, 24, 26, 34,
includes (a) a block 50 which is shown interposed blocks 22, 24,
26, and block 34, and which performs a certain amount of
signal-processing with respect to marking and identifying various
ECG and pacemaker fiducials and timing intervals, (b) a block 52
which generally represents anatomy-attachable ECG and acoustic
sensors that feed data to blocks 24, 26, (c) a block 54 which
represents a patient's pacemaker as well as access to the control
circuitry for that pacemaker, and (d) a block 56 which plays a
direct role in creating a visual output display on a display
screen, or on a strip chart, etc., such as the display-screen
display which is illustrated in FIG. 6 in the drawings.
[0051] A line 58 in FIG. 4 represents a feedback connection between
block 56 and the pacemaker and its control circuitry 54. It should
be understood that feedback information between block 56 and a
pacemaker and its "controls" 54 may be implemented either
automatically under appropriately programmed computer control, or
manually. Such feedback is preferably performed during a
data-gathering time with a patient, whereby the result(s) of
information fed back to the pacemaker, in terms of how that
feedback information affects pacemaker operation, and hence also
affects a patient's hemodynamic behavior, can be observed rapidly
in real time.
[0052] As will be more fully explained with respect to a
description shortly to be given regarding FIG. 6 in the drawings,
it should be apparent how a system and methodology organized in
accordance with FIG. 4 operates in a "pacemaker" setting. To begin
with, and recognizing that, effectively sitting within the
"confines" of blocks 34, 50 in FIG. 4, are the functionalities
afforded by blocks 28, 30, 32 in FIG. 2, blanking and windowing
operations with respect to dealing with phrenic nerve stimulation
are employed as described with respect to FIG. 2. Accordingly, no
"artifact" audio information relating to phrenic nerve stimulation
becomes confusingly processed with true heart-sound information,
and yet a system operator is made immediately aware of any
potential over-stimulation of the heart introduced by an overly
energetic ventricular pacing pulse. Such awareness may be prompted
in any suitable manner, as by a lighted warning element, a sound
notification, or simply by an operator's attention being properly
directed to a audio-signal trace which is provided in the output
display generated by the invention. Referring back for a moment to
FIG. 3 in the drawings, acoustic artifacts, such as artifact 44,
thus do not enter the data stream which is being processed in block
34 to establish reliable heart-sound information, but are employed
to enable pacemaker pacing control with respect to overly
aggressive ventricular pacing pulses. Other audio information,
however, such as that information which is provided by pulses like
those shown at 60, 62 in FIG. 3, is supplied for algorithmic
processing for the purpose of non-confusingly and reliably noting
and presenting information regarding true heart-sound acoustic
data.
[0053] Through the operations of blocks 50, 34, 56 in FIG. 4,
ECG-electrical, and proper heart-sound acoustic, information
becomes processed (i.e., signal-processed) and presented in several
very useful intuitive ways, as are illustrated in FIG. 6, and as
will be discussed shortly herein.
[0054] To visualize the operation of the present invention in a
situation where no pacemaker is involved, one should simply look at
FIG. 4 as if blocks 22 and 54 were not there, and with the
operations of blocks 34 and 50 described, by their respective
labelings, without references made to pacemaker subject matters.
Feedback line, or connection, 58 should also be revisualized as
referring only to other (than pacemaker operation) medical
treatment feedback based upon information developed for display
56.
[0055] FIG. 5 in the drawings is very similar to FIG. 4 as
presented, except that this figure (5) shows an included block 64.
This included block generally represents the fact that the system
and methodology of this invention can readily accommodate the
presence of other kinds (than pacemakers) of cardiovascular-related
devices, such as cardiovascular diagnostic devices, both invasive,
and noninvasive, with respect at least to the reception of useful
diagnostic signals fed through block 22 into the system.
[0056] FIG. 6 in the drawings illustrates, generally at 66, a
multi-component, highly intuitive, computer display-screen output
display, produced by operation of the system and methodology of
this invention. This display (which could also be presented in an
output printing manner) has been generated, in terms of what is
shown operationally in FIGS. 4 and 5, by blocks 56 therein.
[0057] Display 66 includes, generally speaking, (a) a graphical
waveform portion 68 including two, vertically spaced traces 68a,
68b, (b) a time-based geometrical marker portion, or trace, 70, (c)
a geometrical bar-graph portion, or trace, 72, and (d) a
geometrical pie-chart portion, or trace, 74. Traces 70, 72, 74 are
said herein to be keyed to information present in waveform traces
68a, 68b. In display 66, twelve successive cardiac cycles are
shown, these being designated generally A, B, C, D, E, F, G, H, I,
J, K, L. As can clearly be seen in FIG. 6, the events taking place
within each of these twelve respective cardiac cycles, both
electrically and sonically, are quite different from one
another.
[0058] Trace 68a is an electrical waveform trace, which includes a
blend of (1) ECG-electrical signals drawn directly from the
classical V3 electrode Lead position on the anatomy, and (2)
spike-like pulses 40 which are the same in character as pulses 40
illustrated in FIG. 3. These spike-like pulses, thus, represent a
pacemaker's ventricular pacing pulses.
[0059] Trace 68b is an acoustic waveform trace which presents the
acoustical information derived from the recognized V3 site on the
anatomy.
[0060] Traces 68a, 68b, therefore, present a very clear
time-related image of electrical and sound activity associated with
the relevant subject's pacemaker-paced heart activity. These traces
also provide, at a certain level, recognizable information relating
to the subject patient's real time, current hemodynamic behavior
(condition/status).
[0061] Trace 70 provides, projecting above and below a neutral axis
line 76, intuitively displayed heart-sound markers which take the
forms of upwardly and downwardly extending geometrical departures
progressing from the datum of line 76. Those markers which extend
above line 76 are related to systolically-associated heart-sound
data, and those which extend below line 76, and which are
represented by small, darkened rectangles, are related to
diastolically-associated heart-sound signals.
[0062] In the particular display which is shown in FIG. 6, one can
observe that heart sounds S.sub.1 and S.sub.2 provide the upwardly
extending markers relative to line 76, and the S.sub.3 and S.sub.4
heart sounds are those which are illustrated extending below line
76. With respect to those marks which extend below line 76, and the
fact that these are represented in FIG. 6 as small, darkened
rectangles, it is contemplated that the aspect ratios of these
rectangles may be "calibrated" to provide information such as
heart-sound intensity and heart-sound frequency content.
[0063] In bar-graph trace 72, for each of the twelve different
cardiac cycles illustrated in FIG. 6, there is presented a cluster
of (geometrical) rectangles, with four such rectangles appearing in
relation to the first seven cardiac cycles, and three-only such
rectangles being presented with respect to the last five
illustrated cardiac cycles. The particular block illustrations
presented in FIG. 6 which are associated with cardiac cycle D have
been labeled to relate the information contained by these
rectangles to four of the interval measurements which are presented
at the bottom of FIG. 1. Generally speaking, and with respect to
the display approach illustrated in FIG. 6, the vertical dimensions
of these rectangles represent duration times. The combined vertical
dimensions of the blocks representing PADT and AAFT represent the
DT time duration. This summing of the heights of the PADT and AAFT
blocks is specifically illustrated in FIG. 6 with respect to the
blocks that picture information contained in cardiac cycle E.
[0064] Further regarding what is shown in FIG. 6, it will be
observed that cardiac cycles H-L, inclusive, represent a somewhat
elevated heart rate as compared with what is shown in cardiac
cycles A-G, inclusive. What one will also note is that, in the
output information produced in accordance with the invention in
trace 72 regarding these last five illustrated cardiac cycles,
there is no rectangle shown which represents the value PADT. Among
other things that a skilled observer learns from this particular
intuitive display is that the associated subject's heart rate is so
high that there is no ample time to permit pre-atrial diastolic
time (PADT). This condition, of course, would dictate the need to
make some adjustment in pacemaker operation, and very specifically
an adjustment which slows down the subject's heart rate.
[0065] Looking for a moment especially at the presentation
difference which exists in trace 72 with respect to cardiac cycles
B and C, where, in cycle B, pre-atrial diastolic time (PADT) is
quite small, and in cardiac cycle C, that same time is much larger,
a comparison of these two presentations can be visualized as
representing a change in the value of PADT which has been
implemented through appropriate pacemaker feedback operation based
upon the information presented in the bar graph block cluster which
represents cardiac cycle B. It is thus the case that a physician,
clinician, etc., working with a particular patient, can immediately
observe, i.e., on a real time basis, whether such corrective
feedback activity has produced an improvement in hemodynamic
behavior. It will also be apparent that the blocks presented in bar
graph portion 72 furnish a relatively high level of intuitive
information respecting the associated subject's hemodynamic status,
condition, or behavior.
[0066] Pie chart trace 74 presents, in recognizable, classical,
geometrical pie-chart format, two important relatable time
intervals, which are EMAT and (RR-EMAT). Those skilled in the art
will understand that the proportional relationships between these
two intervals as illustrated, for example, with respect to cardiac
cycles D, E, F, and G represent a "better" hemodynamic patient
status than, for example, do the pie-chart "proportional
relationships" which are presented for cardiac cycles A, B, and
H-L, inclusive.
[0067] Accordingly, one can readily see the substantial,
intuitive-information-giving value of output information produced
in accordance with practice of this invention as illustrated in
FIG. 6.
[0068] Turning attention now to FIG. 7 in the drawings, here
indicated at 80, in eleven blocks 82, 84, 86, 88, 90, 92, 94, 96,
98, 100, 102 is the flow architecture of the methodology of the
present invention. Reference numeral 80 can also be viewed as
illustrating generally the system of this invention. From the
methodologic point of view, this methodology, in high-level,
general terms, and expressed first of all in the context of dealing
with a pacemaker patient, takes the form of a method, utilizing
signal-processed ECG-electrical and heart-sound acoustic signal
information, for assessing a pacemaker patient's hemodynamic
condition including the steps of: (1) collecting (block 82), over a
selected time span, for transmission for hemodynamic-condition
signal-processing, simultaneous ECG-electrical and heart-sound
acoustic signals; (2) while so collecting, detecting, electrically,
(block 84) pacemaker-induced ventricular stimulation; and (3) on
detecting such stimulation, creating and applying (block 92) a
selected blanking time which effectively prevents
hemodynamic-condition signal-processing of acoustic signals that
are collected during that blanking time.
[0069] From a systemic point of view, block 82 represents a sensor
structure, block 84 a detecting structure, block 94 a
signal-processing structure, and blocks 96, 98, 100 collectively,
along with portions of block 94, a display structure.
[0070] Returning to the methodologic point of view, methodology 80
further includes the step of generating (block 86), substantially
simultaneously with respect to the beginning of the created and
applied blanking time, an acoustic window which permits examining
(block 88) during that window, of any collected and thus windowed
acoustic signal, in order to determine (block 88) whether that
signal represents an acoustic artifact produced by
pacemaker-induced phrenic nerve stimulation.
[0071] The method of the invention further includes the step of
selectively using the determination of the presence of phrenic
nerve stimulation to modify (block 90) the operation of a patient's
pacemaker.
[0072] Further considering the methodology of the present
invention, it includes, additionally, and in relation to the
application of a blanking time, producing (block 94) a time-based
graphical display containing indicia which are visually descriptive
of selective components of the patient's hemodynamic condition. It
is with respect to this producing step (block 94) that
hemodynamic-condition signal-processing takes place, and thus the
functions of previously mentioned blocks 50, 34, (and in part 56)
can be visualized as taking place (in the context of FIG. 7) within
block 94. This producing step includes establishing (block 98) (a)
an ECG-signal display component, (b) a heart-sound acoustic signal
display component, and (c) an intuitive, heart-sound marker display
designating the time locations of at least one of heart sounds
S.sub.1, S.sub.2, S.sub.3 and S.sub.4. Additionally, the step of
establishing an intuitive heart-sound marker display includes
placing therein (block 100) systolically-associated markers which
are presented above a neutral axis line, and
diastolically-associated sound markers which are displayed below
the same neutral axis line.
[0073] In yet another manner of expressing a portion of the
methodology of the invention, the display producing step (block 94)
involves including in that display (block 96) elements relating to
(a) electromechanical activation time, (b) LV systolic time, (c)
pre-atrial diastolic time, and (d) accelerated atrial filling
time.
[0074] One further way of visualizing the methodology of this
invention is to recognize that it includes utilizing (block 102)
collected ECG-electrical and heart-sound acoustic signals in a
feedback manner to effect changes in the operation of a patient's
pacemaker, and to do this in a fashion which is aimed at improving
the patient's hemodynamic status.
[0075] In a non-pacemaker patient situation, FIG. 7 should be
revisualized as including just blocks 82, 94, 96, 98, 100, 102
interrelated as illustrated (a) by the dashed lines in FIG. 7 that
interconnect blocks 82, 94 and 102, and (b) by the solid lines that
interconnect blocks 94, 96, 98, 100.
[0076] Thus, a preferred system and methodology have been
illustrated and described for this invention, and alternative forms
have been described herein. From a methodologic point of view, the
invention, in relation to a pacemaker patient, features a unique
approach for collecting ECG-electrical and heart-sound acoustic
anatomical signals, for processing those signals in a manner
whereby an event of pacemaker-induced phrenic nerve stimulation
does not produce a condition of confusion with respect to
heart-sound analysis, for allowing information to be gathered
whereby the vigor with respect to which a pacemaker applies pacing
pulses can be adjusted, and for producing, ultimately, results
presentable in a highly intuitive output display that is readable
easily by an expert to assess the current hemodynamic condition of
a particular patient. As has been pointed out, the methodology of
this invention also features the opportunity to apply feedback
control information to a patient's pacemaker in a manner observable
in real time with respect to the effect of a feedback adjustment,
aimed at improving a patient's current hemodynamic status or
condition.
[0077] With respect to a non-pacemaker patient the system performs
all operations just mentioned above except those specifically
focused on dealing with pacemaker operation.
[0078] In all implementations of the invention, medical treatment
feedback (other than pacemaker-control feedback) based on what the
display of the invention shows is possible, and can be viewed
immediately in real time as to feedback result(s).
[0079] Thus, while the invention has been described in a certain
manner herein with certain specific illustrations, it is
appreciated that variations and modifications may be made without
departing from the spirit of the invention.
* * * * *