Systems and methods for valvular regurgitation detection

• US 8,108,034 B2
• Filed: 11/28/2005
• Issued: 01/31/2012
• Est. Priority Date: 11/28/2005
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Patangay, Abhilash, Siejko, Krzysztof Z.
• Primary Examiner(s): Patel, Niketa
• Assistant Examiner(s): ALTER, ALYSSA MARGO
• Application Number:
  US11/287,978
• Publication Number:
  US 20070123943A1
• Time in Patent Office: 2,255 Days
• Field of Search: 600/17, 600/509, 607/17, 607/9
• US Class Current: 600/509
• CPC Class Codes: A61B 7/04 Electric stethoscopes microphones, acoustic transducers therefor H04R
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/36578 controlled by mechanical motion of the heart wall, e.g. measured by an accelerometer or microphone

Abstract

A system comprising an implantable medical device (IMD). The IMD includes an implantable sensor operable to produce an electrical signal representative of mechanical activity of a heart of a subject and a controller circuit coupled to the sensor. The controller circuit includes a wavelet filter module and a valvular regurgitation (VR) calculation module. The wavelet filter module is configured to extract signal energy information from the electrical signal. The energy information includes variation of signal amplitude with frequency and time. The VR calculation module is configured to calculate a measurement of VR for one or more heartbeats using the energy information.

Claims

1. A system comprising:

an implantable medical device (IMD) comprising;

an implantable sensor operable to produce an electrical signal representative of mechanical activity of a heart of a subject; and

a controller circuit coupled to the sensor, wherein the controller circuit includes;

a wavelet filter module including a wavelet filter, the wavelet filter module, configured to;

generate a set of time-frequency representations of the electrical signal; and

produce a wavelet filtered electrical signal using the set of time-frequency representations; and

a valvular regurgitation (VR) calculation module configured to calculate a measurement of VR for one or more heartbeats using a measurement of systolic energy of the wavelet filtered electrical signal during systole and a measurement of diastolic energy of the wavelet filtered electrical signal during diastole.

2. The system of claim 1, wherein the measurement of VR includes a ratio of energy of the electrical signal during systole to energy of the electrical signal during diastole.

3. The system of claim 1, wherein the measurement of VR includes a difference of energy of the electrical signal during systole to energy of the electrical signal during diastole.

4. The system of claim 1, further including a pre-compensation circuit coupled to the sensor and the controller circuit, the pre-compensation circuit including a frequency response to compensate for the frequency response of the sensor.

5. The system of claim 1, wherein the controller circuit further includes a central tendency computation module to calculate a central tendency of VR measurements over a specified number of heartbeats.

6. The system of claim 1, wherein the IMD further includes a stimulation circuit coupled to the controller circuit, the stimulation circuit to provide cardiac resynchronization therapy (CRT) to the heart, and wherein the controller circuit is operable to adjust at least one stimulation parameter related to CRT to reduce an amount of VR indicated by the measurement of VR.

7. The system of claim 6, wherein the controller circuit is operable to adjust an A-V delay between pacing an atrium and a ventricle during the same cardiac cycle to reduce an amount of VR.

8. The system of claim 6, wherein the controller circuit is operable to adjust an interventricular delay between pacing a right ventricle and a left ventricle during the same cardiac cycle to reduce an amount of VR.

9. The system of claim 1, wherein the IMD further includes a communication circuit coupled to the controller circuit, and wherein the system further includes an external device operable to communicate with the IMD to obtain information related to VR.

10. The system of claim 9, wherein the external device is in communication with a network.

11. The system of claim 9, wherein the external device is operable to communicate an alarm indicating increasing VR.

12. The system of claim 9, wherein the external device includes an indication of heart failure (HF) decompensation that uses the information related to VR.

13. The system of claim 12, wherein the indication of HF decompensation uses the information related to VR in addition to information related to at least one other measured physiologic parameter.

14. The system of claim 13, wherein the physiologic parameter is selected from the group consisting of:

intracardiac impedance;

at least one heart sound; and

patient respiration.

15. The system of claim 1, wherein the implantable sensor includes an implantable accelerometer.

16. The system of claim 1, wherein the implantable sensor includes an implantable pressure sensor.

17. The system of claim 1, wherein the implantable sensor includes an implantable microphone.

18. A system comprising:

an implantable medical device (IMD) comprising;

an implantable sensor operable to produce an electrical signal representative of mechanical activity of a heart of a subject;

a sampling circuit coupled to the sensor circuit to produce digital representations of the electrical signal;

a communication circuit; and

a controller circuit coupled to the communication circuit and the sampling circuit, the controller circuit operable to communicate the digital representations; and

an external device comprising;

a communication circuit operable to communicate information with the IMD, the information including the digital representations;

a processor coupled to the communication circuit, the processor including;

a wavelet filter module including a wavelet filter, the wavelet filter module configured to;

generate a set of time-frequency representations of the electrical signal; and

produce a wavelet filtered electrical signal using the set of time-frequency representations; and

a valvular regurgitation (VR) module configured to calculate a measurement of VR for one or more heartbeats using a ratio of a measurement of systolic energy of the wavelet filtered electrical signal during systole to a measurement of diastolic energy of the wavelet filtered electrical signal during diastole.

19. The system of claim 18, wherein the external device includes an IMD programmer and the IMD further includes a stimulation circuit coupled to the controller circuit, the stimulation circuit to provide cardiac resynchronization therapy (CRT) to the heart, and wherein the IMD programmer is operable to adjust at least one stimulation parameter in the IMD related to CRT to reduce an amount of VR indicated by the measurement of VR.

20. The system of claim 19, wherein the IMD programmer is operable to adjust an A-V delay between pacing an atrium and a ventricle during the same cardiac cycle to reduce an amount of VR.

21. The system of claim 19, wherein the IMD programmer is operable to adjust an interventricular delay between pacing a right ventricle and a left ventricle during the same cardiac cycle to reduce an amount of VR.

22. The system of claim 18, wherein the external device is in communication with a server, the server connected to a network, the server including memory, the server operable to trend measurements of VR.

23. The system of claim 22, wherein the server includes an indication of heart failure (HF) decompensation that uses the information related to VR.

24. The system of claim 23, wherein the indication of HF decompensation uses the information related to VR in addition to information related to at least one other measured physiologic parameter to provide an indication of heart failure decompensation, wherein the physiologic parameter is selected from the group consisting of:

intracardiac impedance;

amplitude of at least one heart sound; and

patient respiration.

25. The system of claim 22, wherein the server is operable to provide an alarm indicating heart failure decompensation.

26. A method comprising:

sensing an electrical signal representative of mechanical activity of a heart of a subject using an implantable medical device;

generating a set of time-frequency representations of the electrical signal

producing a wavelet filtered electrical signal using the set of time-frequency representations; and

calculating a measurement of valvular regurgitation (VR) for one or more heartbeats using a ratio of a measurement of systolic energy of the wavelet filtered electrical signal during systole to a measurement of diastolic energy of the wavelet filtered electrical signal during diastole.

27. The method of claim 26, wherein obtaining an electrical signal includes compensating for a sensing frequency response.

28. The method of claim 26, further including calculating a central tendency of the measurement of VR over a predetermined number of beats.

29. The method of claim 26, wherein the method further includes adjusting a stimulation parameter related to cardiac resynchronization therapy (CRT) to reduce an amount of VR indicated by the measurement of VR.

30. The method of claim 29, wherein adjusting a stimulation parameter related to CRT includes adjusting an A-V delay between pacing an atrium and a ventricle during the same cardiac cycle.

31. The method of claim 29, wherein adjusting a pacing parameter related to CRT includes adjusting an interventricular delay between pacing a right ventricle and a left ventricle during the same cardiac cycle.

32. The method of claim 26, further including trending the measurement of VR and displaying the trending over time.

33. The method of claim 26, further including providing an indication of heart failure decompensation using the VR measurement.

34. The method of claim 33, wherein providing an indication of heart failure decompensation using the VR measurement includes using the VR measurement in combination with at least one other measured physiologic parameter.

35. The method of claim 34, wherein the measured physiologic parameter is selected from the group consisting of:

intracardiac impedance;

amplitude of heart sounds; and

patient respiration.