Myocardial performance assessment

• US 20020151938A1
• Filed: 11/15/2001
• Published: 10/17/2002
• Est. Priority Date: 11/17/2000
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Corbucci, Giorgio
• Granted Patent: US 6,792,308 B2
• Time in Patent Office: Days
• US Class Current: 607/25
• CPC Class Codes: A61N 1/36507 controlled by gradient or slope of the heart potential
• CPC Class Codes: A61N 1/3682 with a variable atrioventricular delay
• CPC Class Codes: A61N 1/3684 for stimulating the heart at multiple sites of the ventricle or the atrium
• CPC Class Codes: A61N 1/36842 Multi-site stimulation in the same chamber
• CPC Class Codes: A61N 1/36843 Bi-ventricular stimulation

Abstract

Myocardial performance is assessed using a combination of electrical and mechanical criteria. More specifically, this assessment may be based on a QT interval based on electrogram (EGM) readings and on first and second heart sounds. The timing relationships between the QT interval and the first and second heart sounds can be used to evaluate certain systolic, diastolic, and systolic/diastolic parameters relating to myocardial performance. In addition, these parameters may be used to automatically drive therapies. For example, myocardial performance parameters obtained from the QT interval and from the timing of the first and second heart sounds may be used to optimize the AV delay and to optimize multisite pacing.

Claims

1. A method of cardiac pacing, the method comprising:

detecting a first heart sound and a second heart sound;

determining a QT interval; and

configuring an implantable medical device as a function of the QT interval and of the first and second heart sounds.

2. The method of claim 1, wherein configuring the implantable medical device as a function of the QT interval and of the first and second heart sounds comprises:

calculating a systolic index as a function of the QT interval and of the first and second heart sounds; and

configuring the implantable medical device as a function of the systolic index.

3. The method of claim 2, further comprising:

calculating at least one of a systolic time, a contraction time, and an electrical systolic time as a function of the QT interval and of the first and second heart sounds; and

calculating the systolic index as a function of at least one of the systolic time, the contraction time, and the electrical systolic time.

4. The method of claim 1, wherein configuring the implantable medical device as a function of the QT interval and of the first and second heart sounds comprises:

calculating a diastolic index as a function of the QT interval and of the first and second heart sounds; and

configuring the implantable medical device as a function of the diastolic index.

5. The method of claim 4, further comprising:

calculating at least one of a relaxation time, a diastolic time, and an electrical diastolic time as a function of the QT interval and of the first and second heart sounds; and

calculating the diastolic index as a function of at least one of the relaxation time, the diastolic time, and the electrical diastolic time.

6. The method of claim 1, wherein configuring the implantable medical device as a function of the QT interval and of the first and second heart sounds comprises:

calculating a systolic/diastolic index as a function of the QT interval and of the first and second heart sounds; and

configuring the implantable medical device as a function of the systolic/diastolic index.

7. The method of claim 6, further comprising:

calculating at least one of a contraction time, a relaxation time, a systolic interval, a diastolic interval, and an electrical systolic interval as a function of the QT interval and of the first and second heart sounds; and

calculating the systolic/diastolic index as a function of at least one of the contraction time, the relaxation time, the systolic interval, the diastolic interval, and the electrical systolic interval.

8. The method of claim 1, wherein configuring the implantable medical device comprises selecting at least one of a pacing rate, an atrioventricular (AV) delay, and a left ventricular-right ventricular (LV-RV) delay.

9. The method of claim 1, further comprising detecting the first and second heart sounds using a sensor implanted in a patient.

10. The method of claim 9, wherein the sensor is integral with the implantable medical device.

11. The method of claim 1, further comprising detecting the first and second heart sounds using a sensor external to a patient.

13. The implantable medical device of claim 12, wherein the control arrangement is configured to:

calculate a systolic index as a function of the QT interval and of the first and second heart sounds; and

configure the pulse generator as a function of the systolic index.

14. The implantable medical device of claim 13, wherein the control arrangement is configured to:

calculate at least one of a systolic time, a contraction time, and an electrical systolic time as a function of the QT interval and of the first and second heart sounds; and

calculate the systolic index as a function of at least one of the systolic time, the contraction time, and the electrical systolic time.

15. The implantable medical device of claim 12, wherein the control arrangement is configured to:

calculate a diastolic index as a function of the QT interval and of the first and second heart sounds; and

configure the pulse generator as a function of the diastolic index.

16. The implantable medical device of claim 15, wherein the control arrangement is configured to:

calculate at least one of a relaxation time, a diastolic time, and an electrical diastolic time as a function of the QT interval and of the first and second heart sounds; and

calculate the diastolic index as a function of at least one of the relaxation time, the diastolic time, and the electrical diastolic time.

17. The implantable medical device of claim 12, wherein the control arrangement is configured to:

calculate a systolic/diastolic index as a function of the QT interval and of the first and second heart sounds; and

configure the pulse generator as a function of the systolic/diastolic index.

18. The implantable medical device of claim 17, wherein the control arrangement is configured to:

calculate at least one of a contraction time, a relaxation time, a systolic interval, a diastolic interval, and an electrical systolic interval as a function of the QT interval and of the first and second heart sounds; and

calculate the systolic/diastolic index as a function of at least one of the contraction time, the relaxation time, the systolic interval, the diastolic interval, and the electrical systolic interval.

19. The implantable medical device of claim 12, wherein the control arrangement is configured to select at least one of a pacing rate, an atrioventricular (AV) delay, and a left ventricular-right ventricular (LV-RV) pacing delay.

20. The implantable medical device of claim 12, further comprising an implanted acoustic sensing arrangement to detect the first and second heart sounds.

21. The implantable medical device of claim 20, wherein the implanted acoustic sensing arrangement is integral with the implantable medical device.

22. The implantable medical device of claim 20, wherein the implanted acoustic sensing arrangement comprises at least one of an accelerometer, a vibration sensor, and a piezoelectric sensor.

23. The implantable medical device of claim 12, wherein the first and second heart sounds are detected using a sensor external to a patient.

24. The implantable medical device of claim 12, wherein the implantable medical device is a single-chamber cardiac pacemaker configured to operate in at least one of the group of modes consisting of AAI, AAIR, VVI, VVIR, VVI-ICD, and VVIR-ICD operational modes.

25. The implantable medical device of claim 12, wherein the implantable medical device is a dual-chamber cardiac pacemaker configured to operate in at least one of the group of modes consisting of AAI, AAIR, VVI, VVIR, DDD, DDDR, VVI-ICD, VVIR-ICD, DDD-ICD, and DDDR-ICD operational modes.

27. The medical device system of claim 26, wherein the control arrangement is configured to:

calculate a systolic index as a function of the QT interval and of the first and second heart sounds; and

configure the pulse generator as a function of the systolic index.

28. The medical device system of claim 27, wherein the control arrangement is configured to:

calculate at least one of a systolic time, a contraction time, and an electrical systolic time as a function of the QT interval and of the first and second heart sounds; and

calculate the systolic index as a function of at least one of the systolic time, the contraction time, and the electrical systolic time.

29. The medical device system of claim 26, wherein the control arrangement is configured to:

calculate a diastolic index as a function of the QT interval and of the first and second heart sounds; and

configure the pulse generator as a function of the diastolic index.

30. The medical device system of claim 29, wherein the control arrangement is configured to:

calculate at least one of a relaxation time, a diastolic time, and an electrical diastolic time as a function of the QT interval and of the first and second heart sounds; and

calculate the diastolic index as a function of at least one of the relaxation time, the diastolic time, and the electrical diastolic time.

31. The medical device system of claim 26, wherein the control arrangement is configured to:

calculate a systolic/diastolic index as a function of the QT interval and of the first and second heart sounds; and

configure the pulse generator as a function of the systolic/diastolic index.

32. The medical device system of claim 31, wherein the control arrangement is configured to:

calculate at least one of a contraction time, a relaxation time, a systolic interval, a diastolic interval, and an electrical systolic interval as a function of the QT interval and of the first and second heart sounds; and

calculate the systolic/diastolic index as a function of at least one of the contraction time, the relaxation time, the systolic interval, the diastolic interval, and the electrical systolic interval.

33. The medical device system of claim 26, wherein the control arrangement is configured to select at least one of a pacing rate, an atrioventricular (AV) delay, and a left ventricular-right ventricular (LV-RV) pacing delay.

34. The medical device system of claim 26, wherein the acoustic sensing arrangement is implanted in a patient.

35. The medical device system of claim 34, wherein the acoustic sensing arrangement is integral with an implantable medical device.

36. The medical device system of claim 34, wherein the acoustic sensing arrangement comprises at least one of an accelerometer, a vibration sensor, and a piezoelectric sensor.

37. The medical device system of claim 26, wherein the acoustic sensing arrangement is coupled to a programming arrangement external to a patient.

38. The medical device system of claim 26, wherein the medical device system comprises a single-chamber cardiac pacemaker configured to operate in at least one of the group of modes consisting of AAL AAIR, VVI, VVIR, VVI-ICD, and VVIR-ICD operational modes.

39. The medical device system of claim 26, wherein the medical device system comprises a dual-chamber cardiac pacemaker configured to operate in at least one of the group of modes consisting of AAI, AAIR, VVI, VVIR, DDD, DDDR, VVI-ICD, VVIR-ICD, DDD-ICD, and DDDR-ICD operational modes.

40. The medical device system of claim 26, further comprising a programming arrangement to program the control arrangement.

41. The medical device system of claim 40, wherein the programming arrangement comprises a microprocessor to provide an encoded signal to the control arrangement.

12. An implantable medical device comprising:

a sensing arrangement to sense electrical cardiac signals;

a pulse generator to deliver stimulation pulses to a heart; and

a control arrangement, responsive to the sensing arrangement, to determine a QT interval as a function of the electrical cardiac signals and to configure the pulse generator as a function of the QT interval and of first and second heart sounds.

26. A medical device system comprising:

an electrical sensing arrangement to sense electrical cardiac signals;

an acoustic sensing arrangement to sense first and second heart sounds;

a pulse generator to deliver stimulation pulses to a heart;

at least one pacing lead, coupled to the pulse generator and configured to deliver the stimulation pulses to a chamber of the heart; and

a control arrangement, responsive to the sensing arrangement and configured to determine a QT interval as a function of the electrical cardiac signals and to cause the pulse generator to deliver the stimulation pulses at a rate determined as a function of the QT interval and of the first and second heart sounds.

42. A method of manufacturing an implantable medical device comprising:

providing a sensing arrangement to sense electrical cardiac signals;

providing a pulse generator to deliver stimulation pulses to a heart;

coupling a control arrangement to the sensing arrangement; and

programming the control arrangement to determine a QT interval as a function of the electrical cardiac signals and to configure the pulse generator as a function of the QT interval and of first and second heart sounds.

43. The method of manufacturing an implantable medical device of claim 42, further comprising programming the control arrangement to:

calculate a systolic index as a function of the QT interval and of the first and second heart sounds; and

configure the pulse generator as a function of the systolic index.

44. The method of manufacturing an implantable medical device of claim 43, further comprising programming the control arrangement to:

calculate at least one of a systolic time, a contraction time, and an electrical systolic time as a function of the QT interval and of the first and second heart sounds; and

calculate the systolic index as a function of at least one of the systolic time, the contraction time, and the electrical systolic time.

45. The method of manufacturing an implantable medical device of claim 42, further comprising programming the control arrangement to:

calculate a diastolic index as a function of the QT interval and of the first and second heart sounds; and

configure the pulse generator as a function of the diastolic index.

46. The method of manufacturing an implantable medical device of claim 45, further comprising programming the control arrangement to:

calculate at least one of a relaxation time, a diastolic time, and an electrical diastolic time as a function of the QT interval and of the first and second heart sounds; and

calculate the diastolic index as a function of at least one of the relaxation time, the diastolic time, and the electrical diastolic time.

47. The method of manufacturing an implantable medical device of claim 42, further comprising programming the control arrangement to:

calculate a systolic/diastolic index as a function of the QT interval and of the first and second heart sounds; and

configure the pulse generator as a function of the systolic/diastolic index.

48. The method of manufacturing an implantable medical device of claim 47, further comprising programming the control arrangement to:

calculate at least one of a contraction time, a relaxation time, a systolic interval, a diastolic interval, and an electrical systolic interval as a function of the QT interval and of the first and second heart sounds; and

calculate the systolic/diastolic index as a function of at least one of the contraction time, the relaxation time, the systolic interval, the diastolic interval, and the electrical systolic interval.

49. The method of manufacturing an implantable medical device of claim 42, further comprising programming the control arrangement to select at least one of a pacing rate, an atrioventricular (AV) delay, and a left ventricular-right ventricular (LV-RV) pacing delay.

50. The method of manufacturing an implantable medical device of claim 42, further comprising providing an implanted acoustic sensing arrangement to detect the first and second heart sounds.

51. The method of manufacturing an implantable medical device of claim 50, wherein the implanted acoustic sensing arrangement is integral with the implantable medical device.

52. The method of manufacturing an implantable medical device of claim 50, wherein the implanted acoustic sensing arrangement comprises at least one of an accelerometer, a vibration sensor, and a piezoelectric sensor.

53. The method of manufacturing an implantable medical device of claim 52, wherein the first and second heart sounds are detected using a sensor external to a patient.

54. The method of manufacturing an implantable medical device of claim 42, further comprising configuring the implantable medical device to operate in at least one of the group of modes consisting of AAI, AAIR, VVI, VVIR, DDD, DDDR, VVI-ICD, VVIR-ICD, DDD-ICD, and DDDR-ICD operational modes.

55. An implantable medical device comprising:

means for detecting a first heart sound and a second heart sound;

means for determining a QT interval; and

means for configuring the implantable medical device as a function of the QT interval and of the first and second heart sounds.

56. A medical device system comprising:

means for detecting a first heart sound and a second heart sound;

means for determining a QT interval; and

means for configuring an implantable medical device as a function of the QT interval and of the first and second heart sounds.