Heart sounds template comparison to identify true pacing mode

Patent metadata

Field	Value
Publication number	US-9320906-B2
Application number	US-201414187954-A
Country	US
Kind code	B2
Filing date	Feb 24, 2014
Priority date	Mar 12, 2013
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

An apparatus may include an implantable therapy circuit that provides bi-ventricular pacing to a subject, a heart sound signal sensing circuit that produces a sensed heart sound signal that is representative of at least one heart sound associated with mechanical cardiac activity, a memory circuit to store one or more heart sound templates of cardiac capture, and a comparison circuit that compares a segment of the sensed heart sound signal to the one or more heart sound templates of cardiac capture to identify ventricles in which cardiac capture was induced by the bi-ventricular pacing. In some situations, an indication of the ventricles in which cardiac capture was induced may be generated according to the comparison.

First claim

The claimed invention is:

1. An apparatus comprising:
an implantable therapy circuit configured to provide a bi-ventricular pacing pulse to a subject as part of cardiac pacing therapy, wherein the bi-ventricular pacing pulse includes providing an electrical stimulation pulse to a right ventricle and an electrical stimulation pulse to a left ventricle;
a heart sound signal sensing circuit configured to produce a sensed heart sound signal that is representative of at least one heart sound associated with mechanical cardiac activity of a subject;
a memory circuit configured to store one or more heart sound templates of cardiac capture; and
a comparison circuit configured to:
compare a segment of the sensed heart sound signal to a template heart sound signal representative of ventricular contraction resulting from intrinsic depolarization and at least one of a template heart sound signal representative of right ventricle (RV) capture only, a template heart sound signal representative of left ventricle (LV) capture only, and a template heart sound signal representative of bi-ventricular capture;
identify ventricles in which cardiac capture was induced by the bi-ventricular pacing pulse; and
generate an indication of the ventricles in which capture was induced or an indication of no cardiac capture of a ventricle according to the comparison and providing the indication to at least one of a user or process.

2. The apparatus of claim 1 , including:
a cardiac signal sensing circuit configured to provide a sensed cardiac signal representative of electrical cardiac activity of the subject;
a detection circuit configured to detect an episode of atrial fibrillation using the sensed cardiac signal; and
a control circuit configured to initiate delivery of one or more bi-ventricular pacing pulses during the detected episode of atrial fibrillation,
wherein the comparison circuit is configured to generate an indication of the ventricles in which capture was induced by one or more bi-ventricular pacing pulses provided during the detected episode of atrial fibrillation.

3. The apparatus of claim 1 , wherein the comparison circuit is configured to compare the segment of the sensed heart sound signal to at least one of a template heart sound signal representative of a heart sound signal sensed during pacing of only a right ventricle (RV), a template heart sound signal representative of a heart sound signal sensed during pacing of only a left ventricle (LV), a template heart sound signal representative of a heart sound signal sensed during bi-ventricular pacing, and a template heart sound signal representative of ventricular contraction resulting from intrinsic depolarization; and generate the indication of the ventricles in which capture was induced or an indication of no cardiac capture according to the comparison.

4. The apparatus of claim 1 , wherein the heart sound signal sensing circuit is configured to sense a heart sound signal that includes at least a portion of a sensed S1 heart sound, and wherein the comparison circuit is configured to compare a segment of the sensed heart sound signal that includes the at least a portion of a sensed S1 heart sound to one or more templates representative of an S1 heart sound.

5. The apparatus of claim 1 , wherein the comparison circuit is configured to generate an indication that up dates, according to the comparison, a count of capture induced in the RV only, a count of capture induced in the LV only, a count of capture induced in both ventricles, and a count of lack of capture in the ventricles.

6. The apparatus of claim 1 , including a template circuit configured to generate heart sound templates representative of cardiac capture in the RV, in the LV, and in both ventricles, and generating a heart sound template representative of ventricular contraction due to intrinsic depolarization.

7. The apparatus of claim 6 , including a control circuit configured to initiate a template mode in which one or more electrical stimulation pulses are delivered to one or both ventricles, wherein the electrical stimulation pulses are provided using a stimulation interval that is less than a shortest detected intrinsic depolarization interval, and wherein the template circuit is configured to generate a heart sound template using one or more heart sound signals sensed when providing the one or more electrical stimulation pulses to the one or both ventricles in the template mode.

8. The apparatus of claim 1 , including:
a template circuit configured to generate a candidate heart sound template representative of at least one of cardiac capture in the RV only, cardiac capture in the LV only, cardiac capture in both ventricles, or representative of ventricular contraction resulting from intrinsic depolarization; and
a control circuit configured to receive an indication of acceptance of the candidate template, and wherein the control circuit is configured to initiate a comparison of a segment of a sensed heart sound signal to the candidate template up on receiving the indication of acceptance of the candidate template.

9. The apparatus of claim 1 , including:
a template circuit configured to:
generate a candidate heart sound template representative of cardiac capture resulting from an electrical stimulation pulse delivered to at least one of the RV only, the LV only, or to both ventricles; and
calculate a metric of separation of the candidate heart sound template from a heart sound template representative of ventricular contraction resulting from intrinsic depolarization; and

a control circuit configured to initiate a comparison of a segment of a sensed heart sound signal to the candidate heart sound template according to the calculated metric.

10. The apparatus of claim 1 , including a heart rate detection circuit, wherein the comparison circuit is configured to scale the one or more heart sound templates of cardiac capture in one or both of time and amplitude as a function of detected heart rate, wherein compare the segment of the sensed heart sound signal to one or more scaled heart sound templates.

11. A method comprising
providing, to a subject by an implantable device, a bi-ventricular pacing pulse as part of cardiac pacing therapy, wherein the bi-ventricular pacing pulse includes providing an electrical stimulation pulse to a right ventricle and an electrical stimulation pulse to a left ventricle;
sensing a heart sound signal from the subject in association with the bi-ventricular pacing pulse, wherein a heart sound signal is associated with mechanical activity of the heart of the subject;
comparing by the implantable device, a segment of the sensed heart sound signal to a template heart sound signal representative of ventricular contraction resulting from intrinsic depolarization and at least one of a template heart sound signal representative of right ventricle (RV) capture only, a template heart sound signal representative of left ventricle (LV) capture only, and a template heart sound signal representative of bi-ventricular capture;
identifying ventricles in which cardiac capture was induced by the bi-ventricular pacing pulse; and
generating an indication of the ventricles in which capture was induced or an indication of no cardiac capture of a ventricle according to the comparison and providing the indication to at least one of a user or process.

12. The method of claim 11 , including detecting, by the implantable device, an episode of atrial fibrillation, wherein providing a bi-ventricular pacing pulse includes providing one or more bi-ventricular pacing pulses during the episode of atrial fibrillation, and wherein the generating an indication i

Assignees

• Cardiac Pacemakers Inc

Inventors

• Maskara Barun
• An Qi
• Thakur Pramodsingh Hirasingh
• Thompson Julie A

Classifications

• A61N1/3627 Primary

  for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy · CPC title

• A61B7/04

  Electric stethoscopes · CPC title

• A61N1/36843

  Bi-ventricular stimulation · CPC title

• A61N1/36578

  controlled by mechanical motion of the heart wall, e.g. measured by an accelerometer or microphone · CPC title

• A61N1/3684

  for stimulating the heart at multiple sites of the ventricle or the atrium · CPC title