Controlled delivery of intermittent stress augmentation pacing for cardioprotective effect

1. A cardiac rhythm management device, comprising:

a pulse generator for incorporation into a pacing channel for delivering pacing pulses to a selected ventricular myocardial site;

a controller for controlling the delivery of pacing pulses in accordance with a programmed pacing mode;

wherein the controller is programmed to switch from a normal operating mode to a stress augmentation mode in which a particular region or regions of the ventricular myocardium are subjected to increased mechanical stress as compared with the stress experienced by those regions during the normal operating mode; and,

wherein the controller is programmed to switch to the stress augmentation mode upon expiration of a timer and to cease operating in the stress augmentation mode upon expiration of a specified time period; and,

wherein the controller is programmed to adjust one or more escape intervals when switching to the stress augmentation to increase the frequency of pacing.

2. The device of claim 1 wherein the normal operating mode is a primary pacing mode for delivering ventricular pacing therapy and wherein stress augmentation mode causes a different depolarization pattern than the primary pacing mode.

3. The device of claim 2 wherein the stress augmentation mode excites the ventricular myocardium at a site or sites different from the primary pacing mode.

4. The device of claim 2 wherein the switch from a primary pacing mode to a stress augmentation mode involves switching form bipolar pacing to unipolar pacing or vice-versa.

5. The device of claim 2 wherein the switch from a primary pacing mode to a stress augmentation mode involves switching which electrode of a bipolar pacing lead is the cathode and which electrode is the anode.

6. The device of claim 2 wherein the controller is further programmed to:

deliver pacing pulses to a plurality of ventricular pacing sites; and,

wherein the stress augmentation mode uses at least one pacing channel not used in the primary pacing mode.

7. A device for operating a cardiac rhythm management device, comprising:

a pulse generator for incorporation into a pacing channel for delivering pacing pulses to a selected ventricular myocardial site;

a controller for controlling the delivery of pacing pulses in accordance with a programmed pacing mode;

a sensor for sensing a patient's posture;

wherein the controller is programmed to switch from a normal operating mode to a stress augmentation mode in which a particular region or regions of the ventricular myocardium are subjected to increased mechanical stress as compared with the stress experienced by those regions during the normal operating mode; and,

wherein the controller is programmed to switch to the stress augmentation mode upon receiving a signal from the posture sensor indicating that the patient's posture has changed from a supine position to an erect or sitting position and to cease operating in the stress augmentation mode upon expiration of a specified time period.

8. The device of claim 7 wherein the normal operating mode is a primary pacing mode for delivering ventricular pacing therapy and wherein stress augmentation mode causes a different depolarization pattern than the primary pacing mode.

9. The device of claim 8 wherein the stress augmentation mode excites the ventricular myocardium at a site or sites different from the primary pacing mode.

10. The device of claim 8 wherein the switch from a primary pacing mode to a stress augmentation mode involves switching form bipolar pacing to unipolar pacing or vice-versa.

11. The device of claim 8 wherein the switch from a primary pacing mode to a stress augmentation mode involves switching which electrode of a bipolar pacing lead is the cathode and which electrode is the anode.

12. The device of claim 8 wherein the controller is further programmed to:

deliver pacing pulses to a plurality of ventricular pacing sites; and,

wherein the stress augmentation mode uses at least one pacing channel not used in the primary pacing mode.

13. The device of claim 7 wherein the controller is further programmed to

switch to the stress augmentation mode for a specified time period upon receiving a signal from the posture sensor indicating that the patient's posture has changed from a supine position to an erect or sitting position and if the time of day is within a defined wakeup window as determined by a time stamp.

14. A device for operating a cardiac rhythm management device, comprising:

a pulse generator for incorporation into a pacing channel for delivering pacing pulses to a selected ventricular myocardial site;

a sensing amplifier for incorporation into a sensing channel for detecting cardiac activity;

a controller for controlling the delivery of pacing pulses in accordance with a programmed pacing mode;

wherein the controller is programmed to determine an LF/HF ratio by analyzing data received from the sensing channel;

wherein the controller is programmed to switch from a normal operating mode to a stress augmentation mode in which a particular region or regions of the ventricular myocardium are subjected to increased mechanical stress as compared with the stress experienced by those regions during the normal operating mode; and,

wherein the controller is programmed to switch to the stress augmentation mode when the LF/HF ratio is above a specified threshold value and to cease operating in the stress augmentation mode upon expiration of a specified time period.

15. The device of claim 14 wherein the normal operating mode is a primary pacing mode for delivering ventricular pacing therapy and wherein stress augmentation mode causes a different depolarization pattern than the primary pacing mode.

16. The device of claim 15 wherein the stress augmentation mode excites the ventricular myocardium at a site or sites different from the primary pacing mode.

17. The device of claim 15 wherein the switch from a primary pacing mode to a stress augmentation mode involves switching form bipolar pacing to unipolar pacing or vice-versa.

18. The device of claim 15 wherein the switch from a primary pacing mode to a stress augmentation mode involves switching which electrode of a bipolar pacing lead is the cathode and which electrode is the anode.

19. The device of claim 15 wherein the controller is further programmed to:

deliver pacing pulses to a plurality of ventricular pacing sites; and,

wherein the stress augmentation mode uses at least one pacing channel not used in the primary pacing mode.

20. The device of claim 15 further comprising:

a sensor for measuring a patient's exertion level; and,

wherein the controller is further programmed to cease operating in the stress augmentation mode if the measured exertion level is above a specified threshold.