Third heart sound activity index for heart failure monitoring

• US 8,211,033 B2
• Filed: 08/21/2006
• Issued: 07/03/2012
• Est. Priority Date: 12/24/2003
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Siejko, Krzysztof Z., Green, Laura, Carlson, Gerrard M.
• Primary Examiner(s): Layno, Carl H
• Assistant Examiner(s): SARCIONE, JESSICA LYNN
• Application Number:
  US11/465,878
• Publication Number:
  US 20070078491A1
• Time in Patent Office: 2,143 Days
• Field of Search: 607 4- 6, 607/9, 607 17- 19, 600/481, 600/508, 600/513, 600/514, 600/527, 600/528, 600/586
• US Class Current: 600/528
• CPC Class Codes: A61B 2562/0204 Acoustic sensors
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/02028 Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/4836 Diagnosis combined with treatment in closed-loop systems or methods A61B5/0036 takes precedence
• CPC Class Codes: A61B 5/6847 mounted on an invasive device
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61B 7/00 Instruments for auscultation
• CPC Class Codes: A61B 7/006 Detecting skeletal, cartilage or muscle noise A61B7/003 and A61B7/008 take precedence
• CPC Class Codes: A61B 7/04 Electric stethoscopes microphones, acoustic transducers therefor H04R
• 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: A61N 1/37 Monitoring; Protecting
• CPC Class Codes: A61N 1/3987 characterised by the timing or triggering of the shock

Abstract

A cardiac rhythm management system provides for the trending of a third heart sound (S3) index. The S3 index is a ratio, or an estimate of the ratio, of the number of S3 beats to the number of all heart beats, where the S3 beats are each a heart beat during which an occurrence of S3 is detected. An implantable sensor such as an accelerometer or a microphone senses an acoustic signal indicative heart sounds including S3. An S3 detector detects occurrences of S3 from the acoustic signal. A heart sound processing system trends the S3 index on a periodic basis to allow continuous monitoring of the S3 activity level, which is indicative of conditions related to heart failure.

Claims

1. A cardiac rhythm management system comprising:

an implantable system including;

an implantable acoustic sensor to sense an acoustic signal indicative of at least third heart sounds (S3);

an implant heart sound processor, coupled to the implantable acoustic sensor, to process the acoustic signal; and

an implant telemetry module, coupled to the implant heart sound processor, to transmit the processed acoustic signal; and

an external system communicatively coupled to the implantable system, the external system including;

an external telemetry module to receive the processed acoustic signal; and

an external heart sound module coupled to the external telemetry module, the external heart sound module including means for generating a trend of an S3 index, wherein the S3 index is a ratio of a number of heart beats with S3 detected during a predetermined time period to a total number of heart beats detected during the predetermine time period.

2. The system of claim 1, wherein the implantable system comprises an implantable device and at least one lead connected to the implantable device.

3. The system of claim 2, wherein the implantable acoustic sensor comprises an implantable accelerometer.

4. The system of claim 2, wherein the implantable acoustic sensor comprises an implantable microphone.

5. The system of claim 2, wherein the implantable device comprises a hermetically sealed can to house at least the implantable acoustic sensor and the implant heart sound processor.

6. The system of claim 2, wherein the implantable acoustic sensor is incorporated into the at least one lead.

7. The system of claim 2, wherein the implantable device further comprises a cardiac pacemaker.

8. The system of claim 7, wherein the implantable device further comprises a cardioverter/defibrillator.

9. The system of claim 7, wherein the implantable device further comprises a cardiac resynchronization device.

10. The system of claim 7, wherein the implantable device further comprises a cardiac remodeling control device.

11. The system of claim 2, wherein the external system comprises a medical device programmer communicatively coupled to the implantable device through a wireless telemetry link, the programmer including the external heart sound module.

12. The system of claim 2, wherein the external system comprises:

an external device communicatively coupled to the implantable device through a wireless telemetry link;

a network coupled to the external device; and

a remote device coupled to the network.

13. The system of claim 12, wherein the external device includes the external heart sound module.

14. The system of claim 12, wherein the remote device includes the external heart sound module.

15. A cardiac rhythm management system comprising:

an implantable system including;

a sensing circuit to sense at least one electrogram;

an event detector, coupled to the sensing circuit, to produce a cardiac signal indicative of heart beats; and

an acoustic sensor to sense an acoustic signal indicative of at least third heart sounds (S3);

an external system communicatively coupled to the implantable system; and

a heart sound processing system included in one or more of the implantable system and the external system, the heart sound processing system including a heart sound analyzer adapted to generate a trend of an S3 index using the cardiac signal indicative of heart beats and the acoustic signal indicative of at least S3, the S3 index being a ratio of a number of S3 beats detected during a predetermined time period to a total number of heart beats detected during the predetermine time period, the S3 beats each being a heart beat during which one of S3 is detected.

16. The system of claim 15, wherein the heart sound processing system comprises:

a beat counter adapted to count the heart beats using the cardiac signal indicative of heart beats;

a heart sound detector adapted to detect S3 using the acoustic signal indicative of at least S3; and

a heart sound counter coupled to the heart sound detector, the heart sound counter adapted to count the S3 beats.

17. The system of claim 15, wherein the heart sound processing system comprises a measurement timer adapted to time predetermined measurement sessions and predetermined measurement periods each including a plurality of the predetermined measurement sessions, and the heart sound analyzer comprises:

a ratio calculator adapted to calculate an S3 session ratio being a ratio of a number of the S3 beats counted during one of the predetermined measurement sessions to the number of the heart beats counted during that one of the predetermined measurement sessions; and

an averaging module adapted to calculate an average of the S3 session ratios for one of the predetermined measurement periods.

18. The system of claim 17, wherein the heart sound analyzer further comprises a trend generator adapted to generate a trend of the S3 index as a moving average of the S3 session ratios over the predetermined measurement periods.

19. The system of claim 18, wherein the acoustic sensor comprises an implantable accelerometer.

20. The system of claim 18, wherein the acoustic sensor comprises an implantable microphone.