METHOD AND APPARATUS FOR CLOSED-LOOP INTERMITTENT CARDIAC STRESS AUGMENTATION PACING

• US 20080221636A1
• Filed: 03/06/2007
• Published: 09/11/2008
• Est. Priority Date: 03/06/2007
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Baynham, Tamara Colette, Pastore, Joseph M., Shuros, Allan C., Hopper, Donald L., Arcot-Krishnamurthy, Shantha
• Granted Patent: US 8,615,296 B2
• Time in Patent Office: Days
• US Class Current: 607/18
• 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 1/36514 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 1/36521 the parameter being derived from measurement of an electrical impedance
• CPC Class Codes: A61N 1/36585 controlled by two or more physical parameters

Abstract

A cardiac pacing system controls the progression of a cardiac disorder such as heart failure by delivering cardiac pacing to create or augment regional stress in the heart. The cardiac pacing is delivered intermittently, such as on a periodic basis, according to a cardiac stress augmentation pacing sequence that includes alternating pacing and non-pacing periods. One or more physiological signals are monitored for closed-loop control of the cardiac pacing using baseline characteristics of the cardiac disorder, acute cardiac stress created by the cardiac pacing, and/or risk associated with the cardiac pacing.

Claims

1. A cardiac rhythm management (CRM) system, comprising:

one or more sensors to sense one or more physiological signals;

a signal analyzer coupled to the one or more sensors, the signal analyzer adapted to produce one or more physiological parameters indicative of progression of a cardiac disorder and a level of acute cardiac stress using the one or more physiological signals;

a pacing circuit to deliver cardiac pacing pulses;

a pacing controller, coupled to the signal analyzer and the pacing circuit, to provide feedback control of the delivery of the cardiac pacing pulses using the one or more physiological parameters, the pacing controller including;

a stress augmentation pacing initiator adapted to initiate a cardiac stress augmentation pacing sequence having a sequence duration and including alternating pacing and non-pacing periods, the pacing periods each having a pacing duration during which a plurality of the cardiac pacing pulses is delivered, the non-pacing periods each having a non-pacing duration during which none of the cardiac pacing pulses is delivered;

a stress augmentation pacing timer adapted to time the cardiac stress augmentation pacing sequence; and

a pacing parameter adjuster adapted to adjust one or more pacing parameters for the cardiac stress augmentation pacing sequence using the one or more physiological parameters.

2. The system of claim 1, wherein the one or more sensors comprise one or more baseline characteristic sensors adapted to sense one or more baseline characteristic signals indicative of the progression of the cardiac disorder, the signal analyzer comprises a baseline characteristic analyzer adapted to produce one or more baseline characteristic parameters indicative of the progression of the cardiac disorder using the one or more baseline characteristic signals, and the pacing parameter adjuster is adapted to adjust the pacing parameters using the one or more baseline characteristic parameters.

3. The system of claim 2, wherein the baseline characteristic analyzer is adapted to produce a trend for at least one of the one or more baseline characteristic parameters.

4. The system of claim 2, wherein the one or more baseline characteristic sensors comprise a cardiac sensing circuit to sense one or more cardiac signals, and the baseline characteristic analyzer comprises a heart rate variability (HRV) analyzer adapted to produce an HRV parameter using the one or more cardiac signals.

5. The system of claim 3, wherein the one or more baseline characteristic sensors comprise an activity sensor to sense an activity signal, and the baseline characteristic analyzer comprises an activity analyzer adapted to produce an activity level parameter using the activity signal.

6. The system of claim 3, wherein the one or more baseline characteristic sensors comprise a pressure sensor to sense a blood pressure signal, and the baseline characteristic analyzer comprises a pressure analyzer adapted to produce a systolic blood pressure parameter using the blood pressure signal.

7. The system of claim 3, wherein the one or more baseline characteristic sensors comprise one or more cardiac dimension sensors to sense one or more signals indicative of cardiac dimensions, and the baseline characteristic analyzer comprises a cardiac dimension analyzer adapted to produce one or more cardiac size parameters using the one or more signals indicative of cardiac dimensions, the one or more cardiac size parameters indicative of one or more of a cardiac chamber diameter, a cardiac wall thickness, and a cardiac volume.

8. The system of claim 1, wherein the one or more sensors comprise one or more stress sensors adapted to sense one or more stress signals indicative of the level of acute cardiac stress, the signal analyzer comprises a stress analyzer adapted to produce one or more stress parameters indicative of the level of acute cardiac stress using the one or more stress signals, and the pacing parameter adjuster is adapted to adjust the pacing parameters using the one or more stress parameters.

9. The system of claim 8, wherein the one or more stress sensors comprise an impedance sensor to sense an impedance signal, and the stress analyzer comprises an asynchrony analyzer adapted to produce an asynchrony parameter indicative of a degree of cardiac asynchrony using the impedance signal.

10. The system of claim 8, wherein the one or more stress sensors comprise a pressure sensor to sense a blood pressure signal, and the stress analyzer comprises a contractility analyzer adapted to produce a contractility parameter being a measure of cardiac contractility using the blood pressure signal.

11. The system of claim 1, wherein the one or more sensors comprise one or more risk sensors adapted to sense one or more risk signals indicative of a degree of cardiac risk associated with cardiac stress, the signal analyzer comprises a risk analyzer adapted to produce one or more risk parameters indicative of cardiac risk using the one or more risk signals.

12. The system of claim 11, wherein the one or more risk sensors comprise a pressure sensor to sense a blood pressure signal, and the risk analyzer comprises one or more of a cardiac output analyzer adapted to produce a systolic blood pressure and a diastolic function analyzer adapted to produce a diastolic blood pressure using the blood pressure signal.

13. The system of claim 11, wherein the pacing controller comprises a safety switch adapted to stop the cardiac stress augmentation pacing sequence if the one or more risk parameters fall within a predetermined risk zone defined by one or more threshold values.

14. The system of claim 1, wherein the stress augmentation pacing initiator is adapted to initiate the cardiac stress augmentation pacing sequence according to a cardiac stress augmentation pacing schedule and at least one of the one or more physiological signals.

15. The system of claim 1, wherein the pacing controller comprises a pacing mode switch adapted to switch a pacing mode from a chronic pacing mode to a intermittent pacing mode when the cardiac stress augmentation pacing sequence is initiated and to switch the pacing mode from the intermittent pacing mode to the chronic pacing mode when the cardiac stress augmentation pacing sequence is completed.

16. The system of claim 1, further comprising one or more non-pacing therapy devices adapted to deliver one or more non-pacing therapies, and a non-pacing therapy controller adapted to control the delivery of the one or more non-pacing therapies using the one or more physiological parameters.

17. The system of claim 16, comprising:

an implantable medical device including at least the pacing circuit, the pacing controller, and the non-pacing controller; and

one or more additional medical devices each communicatively coupled to the implantable medical device, the one or more additional medical devices each including at least one of the one or more non-pacing therapy devices.

18. A method for operating a cardiac rhythm management (CRM) system, the method comprising:

sensing one or more physiological signals;

producing one or more physiological parameters indicative of progression of a cardiac disorder and a level of acute cardiac stress using the one or more physiological signals;

delivering cardiac pacing pulses according to a cardiac stress augmentation pacing sequence having a sequence duration and including alternating pacing and non-pacing periods, the pacing periods each having a pacing duration during which a plurality of the cardiac pacing pulses is delivered, the non-pacing periods each having a non-pacing duration during which none of the cardiac pacing pulses is delivered; and

adjusting one or more pacing parameters for the cardiac stress augmentation pacing sequence using the one or more physiological parameters.

19. The method of claim 18, wherein delivering the cardiac pacing pulses according to the cardiac stress augmentation pacing sequence comprises delivering the cardiac pacing pulses using one or more pacing parameters selected to increase a degree of cardiac asynchrony.

20. The method of claim 19, wherein adjusting the one or more pacing parameters comprises adjusting one or more of an atrioventricular delay and an interventricular delay.

21. The method of claim 18, wherein sensing the one or more physiological signals comprises sensing one or more baseline characteristic signals indicative of the progression of the cardiac disorder, producing the one or more physiological parameters comprises producing one or more baseline characteristic parameters indicative of progression of the cardiac disorder using the one or more baseline characteristic signals, and adjusting the one or more pacing parameters comprises adjusting the one or more pacing parameters using the one or more baseline characteristic parameters.

22. The method of claim 21, wherein producing the one or more physiological parameters comprises producing a trend for at least one of the one or more baseline characteristic parameters, and adjusting the one or more pacing parameters comprises adjusting the one or more pacing parameters using the trend.

23. The method of claim 21, wherein sensing the one or more baseline characteristic signals comprises sensing one or more of a cardiac signal, an activity signal, a blood pressure signal, and a cardiac dimension signal, and producing the one or more physiological parameters comprises one or more of producing a heart rate variability (HRV) parameter using the cardiac signal, producing an activity level parameter using the activity signal, producing a systolic blood pressure parameter using the blood pressure signal, and producing one or more cardiac size parameters using the cardiac dimension signal.

24. The method of claim 18, wherein sensing the one or more physiological signals comprises sensing one or more stress signals indicative of a level of acute cardiac stress, producing the one or more physiological parameters comprises producing one or more stress parameters indicative of the level of acute cardiac stress using one or more stress signals, and adjusting the one or more pacing parameters comprises adjusting the one or more pacing parameters using the one or more stress parameters such that the one or more stress parameters approaches a target value region specified with one or more values of the one or more stress parameters.

25. The method of claim 24, wherein sensing the one or more stress signals comprises sensing one or more of an impedance signal, a blood pressure signal and a strain signal, and producing the one or more stress parameters comprises one or more of producing an asynchrony parameter indicative of a degree of cardiac asynchrony using the impedance signal and producing a contractility parameter being a measure of cardiac contractility using at least one of the blood pressure signal and the strain signal.

26. The method of claim 18, wherein sensing the one or more physiological signals comprises sensing one or more risk signals indicative of a degree of cardiac risk associated with cardiac stress, and producing the one or more physiological parameters comprises producing one or more risk parameters indicative of cardiac risk using the one or more risk signals.

27. The method of claim 26, wherein sensing the one or more risk signals comprises sensing one or more of a blood pressure signal and a neurohormonal signal, and producing the one or more risk parameters comprises one or more of producing a systolic blood pressure using the blood pressure signal, producing a diastolic blood pressure using the blood pressure signal, and producing a neurohormonal level using the neurohormonal signal.

28. The method of claim 26, further comprising stopping the delivery of the cardiac pacing pulses according to the cardiac stress augmentation pacing sequence if the one or more risk parameters fall within a predetermined risk zone defined by one or more threshold values.

29. The method of claim 18, further comprising initiating the cardiac stress augmentation pacing sequence on an approximately periodic basis using a stress augmentation pacing period programmable between 3 hours and 96 hours, and programming the sequence duration to a duration between 5 minutes and 90 minutes.

30. The method of claim 18, further comprising initiating the cardiac stress augmentation pacing sequence according to a cardiac stress augmentation pacing schedule and one or more of an activity signal, a posture signal, a respiratory signal, and a cardiac signal.