SMART DELAY FOR INTERMITTENT STRESS THERAPY

• US 20090281591A1
• Filed: 05/06/2009
• Published: 11/12/2009
• Est. Priority Date: 05/08/2008
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Shuros, Allan C., Arcot-Krishnamurthy, Shantha, Shipley, Robert
• Granted Patent: US 8,521,278 B2
• Time in Patent Office: Days
• US Class Current: 607/25
• 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 1/3682 with a variable atrioventricular delay

Abstract

A pacing system delivers cardiac protection pacing to protect the heart from injuries. The pacing system receives a set of inputs and calculates parameters for delivering optimized cardiac protection pacing tailored for different stress levels. The system automatically adjusts heart rate to optimize cardiac protection pacing in a closed-loop system. In one embodiment, a method for delivering pacing pulses for cardiac protection is provided. Intrinsic atrioventricular (AV) intervals are sensed. The intrinsic AV interval and a predetermined equation relating the AV interval to an optimal AV delay are used to provide a maximum positive rate of left ventricular pressure change during systole. An AV delay is calculated using a predetermined percentage of the optimal AV delay to deliver ventricular pacing pulses to provide a desired level of stress for cardiac protective pacing therapy (CPPT) to provide a cardiac conditioning therapy to improve autonomic balance.

Claims

1. A method for delivering pacing pulses, comprising:

sensing intrinsic atrioventricular (AV) intervals;

using the intrinsic AV interval and a predetermined equation relating the AV interval to an optimal AV delay to provide a maximum positive rate of left ventricular pressure change during systole; and

calculating an AV delay using a predetermined percentage of the optimal AV delay to deliver ventricular pacing pulses to provide a desired level of stress for cardiac protective pacing therapy (CPPT) to provide a cardiac conditioning therapy to improve autonomic balance.

2. The method of claim 1, further comprising:

receiving LV electrode location; and

calculating the AV delay using the LV electrode location.

3. The method of claim 1, further comprising:

sensing intrinsic interventricular (VV) interval; and

calculating the AV delay using the sensed intrinsic VV interval.

4. The method of claim 1, further comprising:

sensing QRS width; and

calculating the AV delay using the sensed QRS width.

5. The method of claim 4, wherein calculating the AV delay includes calculating a first AV delay for a wide QRS width and a second AV delay for a narrow QRS width.

6. The method of claim 5, wherein a wide QRS width includes QRS width greater than approximately 150 msec.

7. The method of claim 5, wherein a narrow QRS width includes QRS width greater than approximately 120 msec and less then approximately 150 msec.

8. The method of claim 1, further comprising:

sensing heart rate (HR) in response to the pacing sequences;

dynamically adjusting parameters of the AV delay for the CPPT based on the sensed HR.

9. A method for operating a cardiac pacing device, comprising:

delivering cardiac protective pacing therapy (CPPT) to provide a cardiac conditioning therapy to improve autonomic balance to one or more ventricular sites in an atrial tracking pacing mode with an atrioventricular (AV) delay;

sensing intrinsic AV intervals;

modulating the AV delay based on the sensed intrinsic AV intervals, including calculating AV delay using the intrinsic AV interval and a predetermined equation relating the AV interval to an optimal AV delay, and using a predetermined percentage of the optimal AV delay to deliver ventricular pacing pulses to provide a desired level of stress for the CPPT;

sensing heart rate (HR) in response to the pacing pulses; and

dynamically adjusting parameters of the AV delay for the pacing pulses based on the sensed HR in a closed loop system.

10. The method of claim 9, further comprising:

receiving LV electrode location; and

modulating the AV delay using the LV electrode location.

11. The method of claim 9, further comprising:

sensing intrinsic interventricular (VV) interval; and

modulating the AV delay using the sensed intrinsic VV interval.

12. The method of claim 9, further comprising:

sensing QRS width; and

modulating the AV delay using the sensed QRS width.

13. The method of claim 9, wherein modulating AV delay includes using a short AV delay to provide a small amount of stress during cardioprotective pacing.

14. The method of claim 13, wherein using a short AV delay includes using an AV delay that is 10 to 20 percent of the intrinsic AV interval.

15. The method of claim 9, wherein modulating AV delay includes using a long AV delay to provide a medium amount of stress during cardioprotective pacing.

16. The method of claim 15, wherein using a long AV delay includes using an AV delay that is 80 to 95 percent of the intrinsic AV interval.

17. The method of claim 9, wherein modulating AV delay includes using an AV delay and a VV delay to provide a large amount of stress during cardioprotective pacing.

18. A system, comprising:

a signal input to receive at least one cardiac signal indicative of cardiac events including at least one atrial event and one ventricular event;

an event detector, coupled to the signal input, to detect the at least one atrial event and one ventricular event;

a measurement module, coupled to the event detector, to measure an atrioventricular (AV) time interval between an atrial event and a ventricular event; and

an AV delay calculator coupled to the measurement module, the AV delay calculator adapted to calculate an AV delay using the AV interval and a predetermined equation relating the AV interval to an optimal AV delay to provide a maximum positive rate of left ventricular pressure change during systole, and further adapted to calculate a percentage of the optimal AV delay to deliver ventricular pacing pulses to provide a desired level of stress for cardiac protective pacing therapy (CPPT) to provide a cardiac conditioning therapy to improve autonomic balance.

19. The system of claim 18, further comprising an input for sensing intrinsic interventricular timing.

20. The system of claim 18, further comprising an input for receiving left ventricular (LV) lead location.

21. The system of claim 18, further comprising an input for sensing QRS width.

22. The system of claim 18, further comprising an input for sensing heart rate (HR).