Method and apparatus for optimizing electrical stimulation parameters using heart rate variability

• US 20060161208A1
• Filed: 01/18/2005
• Published: 07/20/2006
• Est. Priority Date: 01/18/2005
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Carlson, Gerrard M., Pastore, Joseph M., Yu, Yinghong, Ding, Jiang, Kramer, Andrew P., Salo, Rodney W.
• Granted Patent: US 7,672,724 B2
• Time in Patent Office: Days
• US Class Current: 607/17
• CPC Class Codes: A61B 5/02405 Determining heart rate variability
• CPC Class Codes: A61B 5/4035 Evaluating the autonomic nervous system
• CPC Class Codes: A61N 1/36114 Cardiac control, e.g. by vagal stimulation stimulating the heart A61N1/362
• CPC Class Codes: A61N 1/36592 controlled by the heart rate variability
• CPC Class Codes: A61N 1/368 comprising more than one electrode co-operating with different heart regions A61N1/3622, A61N1/3627 take precedence

Abstract

A cardiac rhythm management system modulates the delivery of pacing and/or autonomic neurostimulation pulses based on heart rate variability (HRV). An HRV parameter being a measure of the HRV is produced to indicate a patient'"'"'s cardiac condition, based on which the delivery of pacing and/or autonomic neurostimulation pulses is started, stopped, adjusted, or optimized. In one embodiment, the HRV parameter is used to evaluate a plurality of parameter values for selecting an approximately optimal parameter value.

Claims

1. A cardiac rhythm management system comprising:

a pulse output circuit to deliver electrical stimulation pulses;

a sensing circuit to sense a cardiac signal;

a heart rate variability (HRV) measurement circuit, coupled to the sensing circuit, to measure an HRV being a variance in cardiac cycle lengths over a predetermined period of time based on the sensed cardiac signal and to produce an HRV parameter based on the HRV measurement; and

a stimulation control circuit, coupled to the pulse output circuit, the sensing circuit, and the HRV measurement circuit, the stimulation control circuit including a stimulation parameter optimization module adapted to adjust at least one stimulation parameter to an approximately optimal value based on the HRV parameter, the stimulation parameter optimization module including;

a stimulation parameter generator adapted to produce a plurality of parameter values for the at least one stimulation parameter;

a pulse output controller adapted to control the delivery of the electrical stimulation pulses using the plurality of parameter values during a stimulation parameter optimization period; and

a stimulation parameter selector adapted to select the approximately optimal value for the at least one stimulation parameter from the plurality of parameter values, the approximately optimal parameter value corresponding to a maximum value of the HRV parameter measured for the stimulation parameter optimization period.

2. The system of claim 1, wherein the stimulation parameter optimization module comprises an optimization timer to start the stimulation parameter optimization period.

3. The system of claim 2, wherein the optimization timer is programmed to start the stimulation parameter optimization period on a periodic basis.

4. The system of claim 2, wherein the stimulation parameter generator comprises a physiologic parameter measurement circuit adapted to measure at least one physiologic parameter, and wherein the stimulation parameter generator is adapted to produce the plurality of parameter values for the at least one stimulation parameter based on the at least one physiologic parameter, and wherein the pulse output controller is adapted to control the delivery of the plurality of electrical stimulation pulse series each including a plurality of electrical stimulation pulses to be delivered using one parameter value of the plurality of parameter values during the stimulation parameter optimization period.

5. The system of claim 2, wherein the optimization timer is further adapted to stop the stimulation parameter optimization period.

6. The system of claim 5, wherein the stimulation parameter generator comprises a physiologic parameter measurement module to measure at least one physiologic parameter and a dynamic stimulation parameter generator to dynamically produce parameter values of at least one dynamic stimulation parameter based on the at least one physiologic parameter, the pulse output controller is adapted to control the delivery of electrical stimulation pulses using the dynamically produced parameter values of the at least one dynamic stimulation parameter, and the stimulation parameter selector is adapted to identify an approximately optimal value being a value of the dynamic stimulation parameter corresponding to a maximum value of the HRV parameter measured for the stimulation parameter optimization period.

7. The system of claim 1, wherein the pulse output controller comprises a stimulation algorithm execution module to control the delivery of the electrical stimulation pulses by executing a stimulation algorithm during the stimulation parameter optimization period.

8. The system of claim 7, wherein the stimulation algorithm execution module comprise a bradycardia pacing algorithm execution module.

9. The system of claim 7, wherein the stimulation algorithm execution module comprise a cardiac resynchronization therapy (CRT) pacing algorithm execution module.

10. The system of claim 7, wherein the stimulation algorithm execution module comprise a remodeling control therapy (RCT) pacing algorithm execution module.

11. The system of claim 7, wherein the stimulation algorithm execution module comprise an autonomic neurostimulation algorithm execution module.

12. The system of claim 7, wherein the stimulation algorithm execution module comprise a combined pacing and neurostimulation algorithm execution module.

13. The system of claim 1, wherein the pulse output circuit comprises a pacing output circuit to deliver cardiac pacing pulses, and the stimulation control circuit comprises a pacing control circuit including a pacing parameter optimization module to adjust at least one pacing parameter to an approximately optimal value based on the HRV parameter.

14. The system of claim 13, wherein the pacing parameter optimization module comprises an atrioventricular delay (AVD) optimization module adapted to optimize one or more AVDs.

15. The system of claim 13, wherein the pacing parameter optimization module comprises an interventricular delay (IVD) optimization module adapted to optimize one or more IVDs.

16. The system of claim 13, wherein the pacing parameter optimization module comprises a pacing site optimization module adapted to optimize a selection of one or more sites to which the cardiac pacing pulses are delivered.

17. The system of claim 1, wherein the pulse output circuit comprises a neurostimulation circuit to deliver neurostimulation pulses, and the stimulation control circuit comprises a neurostimulation control circuit including a neurostimulation parameter optimization module to adjust at least one neurostimulation parameter to an approximately optimal value based on the HRV parameter.

18. The system of claim 17, wherein the neurostimulation parameter optimization module comprises a stimulation pulse frequency optimization module adapted to optimize one or more stimulation pulse frequencies.

19. The system of claim 17, wherein the neurostimulation parameter optimization module comprises a stimulation site optimization module adapted to optimize a selection of one or more sites to which the neurostimulation pulses are delivered.

20. The system of claim 1, wherein the HRV measurement circuit comprises one or more of a Standard Deviation of Normal-to-Normal intervals (SDNN) generator to produce an SDNN, a Standard Deviation of Averages of Normal-to-Normal intervals (SDANN) generator to produce an SDANN, a Ratio of Low Frequency HRV to High Frequency HRV ratio (LF/HF ratio) generator to produce an LF/HF ratio, an HRV footprint generator to produce an HRV footprint, and a Root-Mean-Square of Successive Differences (RMSSD) generator to produce an RMSSD.

21. The system of claim 1, wherein the HRV measurement circuit comprises an autonomic balance monitor to monitor a parameter indicative of a balance between sympathetic and parasympathetic activities.

22. The system of claim 21, wherein the autonomic balance monitor comprises a Ratio of Low Frequency HRV to High Frequency HRV ratio (LF/HF ratio) generator to produce an LF/HF ratio.

23. A method comprising:

starting a stimulation parameter optimization period;

sensing a cardiac signal;

producing a plurality of parameter values for at least one stimulation parameter;

delivering electrical stimulation pulses using the plurality of parameter values for the at least one stimulation parameter during the stimulation parameter optimization period;

measuring a variance in cardiac cycle lengths over a predetermined period of time to produce at least one heart rate variability (HRV) parameter based on the cardiac signal sensed during the stimulation parameter optimization period;

selecting an approximately optimal value for the at least one stimulation parameter from the plurality of parameter values, the approximately optimal value corresponding to a maximum value of the HRV parameter measured during the stimulation parameter optimization period.

24. The method of claim 23, wherein starting the stimulation parameter optimization period comprises starting the stimulation parameter optimization period on a periodic basis.

25. The method of claim 23, further comprising programming the stimulation parameter optimization period for a period associated with low physical activity level.

26. The method of claim 23, further comprising measuring a physiologic parameter, and wherein producing the plurality of parameter values for the at least one stimulation parameter comprises producing the plurality of parameter values for the at least one stimulation parameter based on the measured physiologic parameter, and delivering the electrical stimulation pulses comprises delivering a plurality of stimulation pulse series each including a plurality of stimulation pulses to be delivered using one parameter value of the plurality of parameter values during the stimulation parameter optimization period.

27. The method of claim 23, further comprising measuring a dynamically changing physiologic parameter, and wherein producing the plurality of parameter values comprises dynamically producing values of a dynamic stimulation parameter based on the dynamically changing physiologic parameter during the stimulation parameter optimization period, delivering the electrical stimulation pulses comprises delivering stimulation pulses using the values of the dynamic stimulation parameter during the stimulation parameter optimization period, and selecting the approximately optimal value for the at least one stimulation parameter including comprises selecting the approximately optimal value from the values of the dynamic stimulation parameter produced during the stimulation parameter optimization period, the approximately optimal value corresponding to a maximum value of the HRV parameter measured for the stimulation parameter optimization period.

28. The method of claim 23, wherein delivering electrical stimulation pulses comprises delivering pacing pulses.

29. The method of claim 28, wherein delivering pacing pulses comprises delivering the pacing pulses by executing a pacing algorithm during the stimulation parameter optimization period, the pacing algorithm using the at least one stimulation parameter.

30. The method of claim 29, wherein executing the pacing algorithm comprises executing at least one of a bradycardia pacing algorithm, a cardiac resynchronization therapy (CRT) pacing algorithm and a remodeling control therapy (RCT) pacing algorithm.

31. The method of claim 30, wherein the at least one stimulation parameter comprises an atrioventricular delay (AVD).

32. The method of claim 30, wherein the at least one stimulation parameter comprises an interventricular delay (IVD).

33. The method of claim 30, wherein the at least one stimulation parameter comprises a pacing site parameter identifying sites to which the pacing pulses are delivered.

34. The method of claim 23, wherein delivering the electrical stimulation pulses comprises delivering neurostimulation pulses.

35. The method of claim 34, wherein delivering neurostimulation pulses comprises delivering the neurostimulation pulses by executing a neurostimulation algorithm during the stimulation parameter optimization period, the neurostimulation algorithm using the at least one stimulation parameter.

36. The method of claim 35, wherein the at least one stimulation parameter comprises a stimulation frequency.

37. The method of claim 35, wherein the at least one stimulation parameter comprises a stimulation site parameter identifying sites to which the neurostimulation pulses are delivered.

38. The method of claim 23, wherein measuring HRV to produce the HRV parameter comprises measuring HRV to produce one or more of a Standard Deviation of Normal-to-Normal intervals (SDNN), a Standard Deviation of Averages of Normal-to-Normal intervals (SDANN), a Ratio of Low Frequency HRV to High Frequency HRV ratio (LF/HF ratio), an HRV footprint, and a Root-Mean-Square of Successive Differences (RMSSD).

39. The method of claim 23, wherein measuring HRV to produce the HRV parameter comprises measuring HRV to produce a parameter indicative of a balance between sympathetic and parasympathetic activities.

40. The method of claim 39, wherein measuring HRV to produce the parameter indicative of the balance between sympathetic and parasympathetic activities comprises producing a Ratio of Low Frequency HRV to High Frequency HRV ratio (LF/HF ratio).