Method and apparatus for optimization of cardiac resynchronization therapy using heart sounds

• US 7,953,484 B2
• Filed: 03/19/2007
• Issued: 05/31/2011
• Est. Priority Date: 06/10/2004
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Lincoln, William C., Carlson, Gerrard M., Brockway, Marina
• Primary Examiner(s): Bockelman; Mark W
• Assistant Examiner(s): So; Elizabeth K
• Application Number:
  US11/687,812
• Publication Number:
  US 20070162080A1
• Time in Patent Office: 1,534 Days
• Field of Search: 607/1, 607/2, 607/9, 607 17- 18, 600/508, 600/509, 600/513, 600/528
• US Class Current: 607/17
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61B 5/0809 by impedance pneumography
• CPC Class Codes: A61B 5/113 occurring during breathing
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61B 7/00 Instruments for auscultation
• CPC Class Codes: A61N 1/36514 controlled by a physiological quantity other than heart potential, e.g. blood pressure controlled by two or more physical parameters A61N1/36585
• CPC Class Codes: G06F 2218/00 Aspects of pattern recognition specially adapted for signal processing

Abstract

A cardiac rhythm management system provides for assessment of cardiac mechanical dyssynchrony based on heart sound morphology and optimization of pacing parameters based on the effect of pacing on the cardiac mechanical dyssynchrony assessment. A degree of cardiac mechanical dyssynchrony is measured by the time delay between tricuspid valve closure and mitral valve closure and/or the time delay between pulmonary valve closure and aortic valve closure. A cardiac resynchronization therapy is optimized by determining therapy parameters to provide an approximately minimum degree of cardiac mechanical dyssynchrony by cardiac pacing.

Claims

1. A system for pacing a heart having cardiac chambers including right and left ventricles and cardiac valves including tricuspid, mitral, pulmonary, and aortic valves, the system comprising:

a heart sound input to receive one or more signals indicative of heart sounds;

a heart sound detector coupled to the heart sound input, the heart sound detector adapted to detect predetermined type heart sounds using the received one or more signals, the predetermined type heart sounds having morphological features indicative of one or more time intervals each between closures of a first cardiac valve and a second cardiac valve in a cardiac cycle, the one or more time intervals each indicative of cardiac mechanical dyssynchrony;

a heart sound morphology analyzer coupled to the heart sound detector, the heart sound morphology analyzer adapted to measure one or more dyssynchrony parameters each from one heart sound of the detected predetermined type heart sounds and indicative of a time interval of the one or more time intervals; and

a pacing parameter optimization module coupled to the heart sound morphology analyzer, the pacing parameter optimization module adapted to determine one or more approximately optimal pacing parameters using the one or more dyssynchrony parameters, the one or more approximately optimal pacing parameters providing for an approximately minimum degree of cardiac mechanical dyssynchrony as indicated by the one or more dyssynchrony parameters.

2. The system of claim 1, wherein the heart sound detector is adapted to detect first heart sounds (S1), and the heart sound morphology analyzer comprises an S1 measurement module adapted to measure one or more parameters each indicative of a first time interval between a tricuspid valve closure and a mitral valve closure using the detected S1.

3. The system of claim 1, wherein the heart sound detector is adapted to detect second heart sounds (S2), and the heart sound morphology analyzer comprises an S2 measurement module adapted to measure one or more parameters each indicative of a second time interval between a pulmonary valve closure and an aortic valve closure using the detected S2.

4. The system of claim 1, wherein the heart sound detector is adapted to detect first heart sounds (S1) and second heart sounds (S2), and the heart sound morphology analyzer comprises:

an S1 measurement module adapted to measure one or more parameters each indicative of a first time interval between a tricuspid valve closure and a mitral valve closure using the detected S1; and

an S2 measurement module adapted to measure one or more parameters each indicative of a second time interval between a pulmonary valve closure and an aortic valve closure using the detected S2.

5. The system of claim 4, wherein the heart sound input is configured to receive a first signal indicative of S1 sensed from the right ventricle (S1_Rv) and S2 sensed from the rightventricle (S2_Rv) and a second signal indicative of at least S1 sensed from the left ventricle (S1_LV) and S2 sensed from the left ventricle (S2_LV), the heart sound detector is adapted to detect S1_RV and S2_RV using the received first signal and detect S1_LV and S2_LV using the received second signal, the S1 measurement module is adapted to measure an S1 delay being a time interval between S1_RV and S1_LV, and the S2 measurement module is adapted to measure an S2 delay being a time interval between S2_RV and S2_LV.

6. The system of claim 4, wherein the S1 measurement module is adapted to measure an S1 width, and the S2 measurement module is adapted to measure an S2 width.

7. The system of claim 4, wherein the S1 measurement module is adapted to measure an S1 delay being a time interval between a morphological feature indicative of the tricuspid valve closure and a morphological feature indicative of the mitral valve closure, and the S2 measurement module is adapted to measure an S2 delay being a time interval between a morphological feature indicative of the pulmonary valve closure and a morphological feature indicative of the aortic valve closure.

8. The system of claim 1, wherein the parameter optimization module is adapted to optimize one or more of a pacing site, an atrioventricular delay, and an interventricular delay.

9. A method for operating a cardiac pacemaker, the method comprising:

receiving one or more heart sound signals;

detecting predetermined type heart sounds having morphological features indicative of one or more time intervals each between closures of a first cardiac valve and a second cardiac valve in a cardiac cycle, the one or more time intervals each indicative of cardiac mechanical dyssynchrony;

measuring one or more dyssynchrony parameters each from one heart sound of the detected predetermined type heart sounds and indicative of a time interval of the one or more time intervals; and

determining one or more approximately optimal pacing parameters using the one or more dyssynchrony parameters, the one or more approximately optimal pacing parameters providing for an approximately minimum degree of cardiac mechanical dyssynchrony as indicated by the one or more dyssynchrony parameters.

10. The method of claim 9, comprising sensing one or more heart sound signals indicative of one or more of first heart sounds (S1) and second heart sounds (S2).

11. The method of claim 10, wherein measuring the one or more dyssynchrony parameters indicative of the one or more time intervals comprises measuring one or more of an S1 width and an S2 width.

12. The method of claim 10, wherein measuring the one or more dyssynchrony parameters indicative of the one or more time intervals comprises measuring one or more of an S1 delay and an S2 delay, the S1 delay representative of a time interval between a tricuspid valve closure and a mitral valve closure during a cardiac cycle, the S2 delay representative of a time interval between a pulmonary valve closure and an aortic valve closure during a cardiac cycle.

13. The method of claim 12, comprising sensing a first heart sound signal from a right ventricle (RV) and sensing a second heart sound signal from a left ventricle (LV).

14. The method of claim 13, comprising sensing a first heart sound signal from RV and a second heart sound from LV, the first heart sound signal indicative of S1 sensed from the RV (S1_RV) and S2 sensed from the RV (S2_RV), the second heart sound signal indicative of S1 sensed from the LV (S1_LV) and S2 sensed from the LV (S2_LV), and wherein measuring the S1 delay comprises measuring the S1 delay being a time interval between S1_RV and S1_LV, and measuring the S2 delay comprises measuring the S2 delay being a time interval between S2_RV and S2_LV.

15. The method of claim 9, wherein determining the one or more pacing parameters comprises selecting one or more pacing sites to which pacing pulses are delivered.

16. The method of claim 9, wherein determining the one or more pacing parameters comprises determining one or more atrioventricular delays at which ventricular pacing pulses are delivered.

17. The method of claim 9, wherein determining the one or more pacing parameters comprises determining one or more interventricular delays at which ventricular pacing pulses are delivered.

18. A cardiac pacing system, comprising:

means for detecting predetermined type heart sounds from one or more heart sound signals, the predetermined type heart sounds having morphological features indicative of one or more time intervals each between closures of a first cardiac valve and a second cardiac valve, the one or more time intervals each indicative of cardiac mechanical dyssynchrony;

means for measuring one or more dyssynchrony parameters each from one heart sound of the detected predetermined type sounds and indicative of a time interval of the one or more time intervals; and

means for determining one or more approximately optimal pacing parameters using the one or more dyssynchrony parameters, the one or more approximately optimal pacing parameters providing for an approximately minimum degree of cardiac mechanical dyssynchrony as indicated by the one or more dyssynchrony parameters.

19. The system of claim 18, comprising implantable means for sensing the one or more heart sound signals.

20. The system of claim 19, further comprising means for producing at least one dyssynchrony parameter indicative of a degree of cardiac mechanical dyssynchrony using the detected heart sounds having morphological features indicative of one or more time intervals each between closures of the first cardiac valve and the second cardiac valve in a cardiac cycle.