Implantable cardiac stimulation device for monitoring heart sounds to detect progression and regression of heart disease and method thereof

• US 6,643,548 B1
• Filed: 04/06/2000
• Issued: 11/04/2003
• Est. Priority Date: 04/06/2000
• Status: Active Grant

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Inventors: Park, Euljoon, Mai, Junyu
• Primary Examiner(s): Jastrzab, Jeffrey R.
• Assistant Examiner(s): Oropeza, Frances P.
• Application Number:
  US09/544,596
• Time in Patent Office: 1,307 Days
• Field of Search: 600/374, 600/509, 600/513, 600/514, 600/515, 600/516, 600/517, 600/518, 600/519, 600/521, 600/528, 607/4, 607/5, 607/7, 607/9, 607/11, 607/14, 607/17, 607/18, 607/19, 607/25, 607/62, 607/119
• US Class Current: 607/17
• 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 1/36528 the parameter being measured by means of ultrasound
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371

Abstract

A system and method for use in an implantable cardiac device permits the monitoring of progression and regression in heart disease, such as congestive heart failure. During a monitoring period, a sensing circuit produces an electrogram signal of the patient'"'"'s heart and a sound sensor produces a phonocardiogram of the patient'"'"'s heart. A processor determines a predetermined characteristic of the heart sounds, such as amplitude, time intervals between selected heart sounds, and time intervals between selected heart sound and selected electrogram features for each cardiac cycle occurring during a monitoring period. The predetermined characteristics are thereafter averaged and stored in a memory for later retrieval. Relative changes in the average time intervals over time provides an indication of the progression or regression of the heart disease.

Claims

1. In an implantable cardiac stimulation device, a system for monitoring a progression and regression of a patient'"'"'s heart disease, the system comprising:

a sensing circuit that senses a patient'"'"'s cardiac signals;

an acoustic sensor that detects a patient'"'"'s heart sounds;

a processor programmed to determine relative changes in at least one heart sound, and to provide information related to the relative changes indicating whether there is progression or regression in the patient'"'"'s heart disease;

timing circuitry, coupled to the sensing circuit and the acoustic sensor, that is operative to determine a time interval between a selected heart sound and a selected cardiac event within the patient'"'"'s cardiac signals; and

wherein the processor is programmed to determine relative changes in the time interval between the selected heart sound and the selected cardiac event within the patient'"'"'s cardiac signal, the processor further being programmed to detect a progression of heart disease based on the relative changes in the time interval.

2. The system of claim 1, further comprising:

timing circuitry, coupled to the sensing circuit and the acoustic sensor, for determining a time interval between a selected heart sound and a selected cardiac event within the patient'"'"'s cardiac signals; and

wherein the processor is programmed to determine relative changes in the time interval between the selected heart sound and the selected cardiac event within the patient'"'"'s cardiac signal.

3. The system of claim 2, wherein the selected heart sound is a patient'"'"'s first heart sound, S1, and the selected cardiac event is an R-wave, so that the time interval corresponds to an interval from each R-wave to the first heart sound following a respective R-wave.

4. The system of claim 1, further comprising:

timing circuitry, coupled to the sensing circuit and the acoustic sensor, for determining a time interval between two heart sounds; and

the processor is programmed to determine relative changes in the time interval between the two heart sounds.

5. The system of claim 4, wherein the two heart sounds correspond to a first heart sound, S1, and a second heart sound, S2.

6. The system of claim 1, further comprising:

detecting circuitry, coupled to the acoustic sensor, for determining the absence or presence of selected heart sounds; and

wherein the processor is programmed to detect relative changes in the absence or presence of selected heart sounds.

7. The system of claim 1, further comprising:

amplitude detecting circuitry, coupled to the acoustic sensor, for determining the amplitude of selected heart sounds; and

wherein the processor is programmed to detect relative changes in the amplitude of selected heart sounds.

8. The system of claim 1, further comprising:

a pulse generator for generating stimulation pulse therapy; and

wherein the processor is programmed to adjust the stimulation pulse therapy in response to the relative changes in the at least one heart sound to improve hemodynamics.

9. The system of claim 1, wherein the processor is programmed to determine the relative changes in the at least one heart sound during a predetermined time period each day.

10. The system of claim 1, further comprising:

an activity detector that detects activity of the patient; and

wherein the processor determines the relative changes in the at least one heart sound while the patient is inactive.

11. The system of claim 1, wherein the processor is further programmed to average the relative changes in the at least one heart sound over a predetermined period of time.

12. The system of claim 6, further comprising:

a memory that stores the relative changes in the at least one heart sound;

and

a telemetry circuit that transmits the relative changes in the at least one heart sound to an external receiver.

13. In an implantable cardiac stimulation device, a system for monitoring a progression and regression of a patient'"'"'s heart disease, the system comprising;

sensing means for providing an electrogram signal representing electrical activity of a patient'"'"'s heart;

sound sensing means for providing a heart sound signal of the patient'"'"'s heart; and

determining means for determining relative changes in at least one heart sound, and to provide information related to the relative changes indicating whether there is progression or regression in the patient'"'"'s heart disease, wherein the determining means comprises time span determining means for determining time spans between selected heart sounds in the heart sound signal and selected features in the electrogram signal, wherein the determining means further comprises means for detecting a progression of heart disease based on relative changes in the time spans between selected heart sounds in the heart sound signal and selected features in the electrogram signal.

14. The system of claim 13, wherein the determining means comprises:

time span determining means for determining time spans between selected heart sounds in the heart sound signal and selected features in the electrogram signal, relative changes in the time spans over time indicating whether there is a progression or regression in the patient'"'"'s heart disease.

15. The system of claim 14, wherein the time spans are time spans between each R wave and a first heart sound following a respective R wave for each sensed cardiac cycle of the patient'"'"'s heart.

16. The system of claim 13, wherein the determining means comprises:

time span determining means for determining time spans between selected ones of the heart sounds, wherein relative changes in the time spans over time indicates whether there is a progression or regression in the heart disease.

17. The system of claim 16, wherein the time spans comprise time spans between a first heart sound and a second heart sound following the first heart sound for each sensed cardiac cycle of the patient'"'"'s heart.

18. The system of claim 14, wherein the time span determining means determines the time spans for cardiac cycles of the patient'"'"'s heart sensed during a fixed time period each day.

19. The system of claim 14, further comprising:

activity detecting means for detecting activity of the patient; and

wherein the time span determining means determines the time spans for heart sounds and electrogram features sensed while the patient is inactive.

20. The system of claim 13, further comprising:

storing means for storing the relative changes in the at least one heart sound; and

telemetry means for conveying the relative changes to the at least one heart sound to an external receiver.

21. The system of claim 13, wherein a healthy patient is defined as having at least a first and a second heart sound, and a patient with congestive heart disease, CHF, is defined as having at least one of a third or fourth heart sound, further comprising:

means for determining the absence or presence of the patient'"'"'s third and fourth heart sounds; and

wherein the determining means determines relative changes in the absence or presence of selected heart sounds so as to detect whether a patient has developed CHF.

22. The system of claim 13, further comprising:

amplitude detecting means, coupled to the sound sensing means, for determining the amplitude of selected heart sounds; and

wherein the determining means determines relative changes in the amplitude of selected heart sounds and correlate these changes to healthy patients or heart disease patients.

23. The system of claim 13, further comprising:

pulse generating means for generating stimulation pulse therapy; and

wherein the determining means further includes means for adjusting the stimulation pulse therapy in response to the relative changes in the at least one heart sound to improve hemodynamics in patients who have heart disease.

24. In an implantable cardiac stimulation device, a method of monitoring a progression or regression of a patient'"'"'s heart disease, the method comprising the steps of:

sensing electrical activity of a patient'"'"'s heart to provide an electrogram signal;

sensing emitted sounds of the patient'"'"'s heart to provide a heart sound signal including at least one of a first heart sound, S1, a second heart sound, S2, a third heart sound, S3, and a fourth heart sound, S4;

processing the electrogram and the heart sound signals to determine relative changes in a predetermined characteristic of selected heart sounds, the predetermined characteristic being selected from at least one of first time duration between an R-wave and S1, second time duration between S1 and S2, and a third time duration between S2 and S1;

detecting a progression of heart disease based on a change in the selected time duration; and

providing information related to the relative changes in at least one of such characteristics to indicate whether a there is a progression or regression in the patient'"'"'s heart disease.

25. The method of claim 24, further comprising the step of averaging the predetermined heart sound characteristic.

26. The method of claim 24, wherein the processing step includes determining the predetermined heart sound characteristic during a predetermined time period each day.

27. The method of claim 24, further comprising the step of communicating the predetermined heart sound characteristic on an external receiver for display thereon.

28. The method of claim 24, further comprising the step of detecting activity of the patient and wherein the predetermined heart sound characteristics are sensed while the patient is inactive.

29. In an implantable cardiac stimulation device, a system for monitoring a progression and regression of heart disease in a patient'"'"'s heart, the system comprising:

an acoustic sensor that detects heart sounds;

a control circuit, coupled to the acoustic sensor, configured to determine relative changes in at least one heart sound over an extended period of time, the control circuit providing an indication that such relative changes over the extended period of time indicates one of the progression or regression in the patient'"'"'s heart disease;

a sensing circuit, coupled to the control circuit, that senses R-waves;

detection circuitry, coupled to the acoustic sensor and the sensing circuit, that discriminates between one or more of a first heart sound, S1, a second heart sound, S2, a third heart sound, S3, a fourth heart sound, S4, and a respective R-wave;

timing circuitry, coupled to the detection circuitry and the control circuit, that determines a temporal relationship between one or more of the first heart sound, the second heart sound, the third heart sound, the fourth heart sound, and the respective R-wave; and

wherein the processor is programmed to determine relative changes in one or more of the temporal relationships and to detect a progression of heart disease based on the relative changes in one or more of the temporal relationships.

30. The system of claim 29, further comprising:

a memory, coupled to the control circuit, that stores the relative changes in the at least one heart sound over the extended period of time; and

a telemetry circuit, coupled to the memory and the control circuit, that transmits the relative changes in the at least one heart sound to an external receiver that displays the relative changes over the extended period of time.

31. The system of claim 29, further comprising:

a sensing circuit, coupled to the control circuit, that senses R-waves;

detection circuitry, coupled to the acoustic sensor and the sensing circuit, that discriminates between one or more of a first heart sound, S1, a second heart sound, S2, a third heart sound, S3, a fourth heart sound, S4, and a respective R-wave; and

timing circuitry, coupled to the detection circuitry and the control circuit, that determines a temporal relationship between one or more of the first heart sound, the second heart sound, the third heart sound, the fourth heart sound, and the respective R-wave; and

wherein the control circuitry is programmed to determine relative changes in one or more of the temporal relationships.

32. The system of claim 29, further comprising:

amplitude measuring circuitry, coupled to the acoustic sensor, that measures the amplitude of selected heart sounds; and

wherein the control circuitry is programmed to detect relative changes in the amplitude of selected heart sounds.

33. The system of claim 29, further comprising:

an activity detector that detects activity level of the patient; and

wherein the control circuitry determines the relative changes in the at least one heart sound while the patient is inactive.

34. The system of claim 33, wherein the control circuit is further configured to average the relative changes in the at least one heart sound over a predetermined period of time while the patient is inactive.

35. The system of claim 29, further comprising:

a pulse generator, coupled to the control circuit, that generates stimulation pulse therapy; and

wherein the control circuit is configured to adjust the stimulation pulse rate in response to a trend in the relative changes in the at least one heart sound to improve hemodynamics.

36. In an implantable cardiac stimulation device, a system for monitoring a progression and regression of a patient'"'"'s heart disease, the system comprising:

an acoustic sensor that detects heart sounds;

a control circuit, coupled to the acoustic sensor, configured to determine a plurality of relative changes in at least one heart sound, and to provide trend data as to whether there is progression or regression in the patient'"'"'s heart disease;

a sensing circuit that senses selected cardiac events;

timing circuitry, coupled to the sensing circuit, the control circuit and the acoustic sensor, that determines a time interval between a selected heart sound and a selected cardiac event; and

wherein the control circuit is configured to provide the trend data of the relative changes in the time interval between the selected heart sound and the selected cardiac event and to detect a progression of heart disease based on the relative changes in the time interval between the selected heart sound and the selected cardiac event.

37. The system of claim 36, further comprising:

a sensing circuit that senses selected cardiac events;

timing circuitry, coupled to the sensing circuit, the control circuit and the acoustic sensor, that determines a time interval between a selected heart sound and a selected cardiac event; and

wherein the control circuit is configured to provide the trend data of the relative changes in the time interval between the selected heart sound and the selected cardiac event.

38. The system of claim 36, further comprising:

timing circuitry, coupled to the control circuit and the acoustic sensor, that determines a time interval between two heart sounds; and

the control circuit is configured to provide the trend data of the relative changes in the time interval between the two heart sounds.

39. The system of claim 36, further comprising:

detecting circuitry, coupled to the control circuit and the acoustic sensor, that determines the absence or presence of selected heart sounds; and

wherein the control circuit is configured to provide the trend data of the relative changes in the absence or presence of selected heart sounds.

40. The system of claim 36, further comprising:

amplitude detecting circuitry, coupled to the control circuit and the acoustic sensor, that determines the amplitude of selected heart sounds; and

wherein the control circuit is configured to detect relative changes in the amplitude of selected heart sounds.

41. The system of claim 36, further comprising:

a pulse generator that generates stimulation pulse therapy; and

wherein the control circuit is configured to increase the stimulation pulse rate in response to a determination of the progression of heart disease to improve hemodynamics.