System and Method for Promoting Intrinsic Conduction Through Atrial Timing

• US 20070293900A1
• Filed: 06/15/2006
• Published: 12/20/2007
• Est. Priority Date: 06/15/2006
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Sheldon, Todd J., Belk, Paul A., Sweeney, Michael O.
• Granted Patent: US 7,565,196 B2
• Time in Patent Office: Days
• US Class Current: 607/9
• CPC Class Codes: A61F 2002/30677 Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body
• CPC Class Codes: A61F 2002/3068 the pharmaceutical product being in a reservoir
• CPC Class Codes: A61F 2002/444 for replacing the nucleus pulposus
• CPC Class Codes: A61F 2002/4666 for measuring force, pressure or mechanical tension
• CPC Class Codes: A61F 2250/0067 Means for introducing or releasing pharmaceutical products into the body
• CPC Class Codes: A61F 2250/0068 the pharmaceutical product being in a reservoir
• CPC Class Codes: A61K 9/0024 Solid, semi-solid or solidifying implants, which are implanted or injected in body tissue compositions for intravenous administration, normal injectable solutions or dispersions for, e.g. subcutaneous administration A61K9/0019; brain implants A61K9/0085; (coated) prostheses, catheters or stents A61L
• CPC Class Codes: A61M 31/002 Devices for releasing a drug at a continuous and controlled rate for a prolonged period of time artificial gland structures or devices A61F2/022; intra-uterine contraceptive devices A61F6/14; tampons for introducing into the vagina A61F13/20, A61L15/00; suppositories or bougies for intra-vaginal or intra-uterine application A61K9/02; physical forms of medicinal preparations for sustained or differential drug release A61K9/20, A61K9/50
• 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 1/368 comprising more than one electrode co-operating with different heart regions A61N1/3622, A61N1/3627 take precedence
• CPC Class Codes: A61N 1/3682 with a variable atrioventricular delay

Abstract

An atrial based pacing protocol promotes intrinsic conduction. An entire cardiac cycle is monitored for ventricular activity and permitted to lapse with ventricular activity. Ventricular pacing is available in a cardiac cycle immediately subsequent to such a skipped beat. When monitoring for intrinsic ventricular events, an event is expected within a given window. If no such event is detected, the cardiac cycle in truncated, leading to a shorter cycle that is devoid of ventricular activity. The subsequent cycle has a high likelihood of a ventricular sensed event and a greater than normal AV interval is provided prior to pacing.

Claims

1. A method comprising:

operating an implantable medical device according to a ventricular pacing protocol (VPP) wherein ventricular pacing is precluded in a given cardiac cycle where a ventricular event occurred in a cardiac cycle immediately prior to the given cardiac cycle;

establishing an A-A interval;

initiating a first AV interval timer at the initiation of the given cardiac cycle;

sensing for ventricular events;

scheduling an atrial pacing pulse prior to the termination of the A-A interval if no ventricular event is sensed within the duration of the AV interval timer.

2. The method of claim 1, further comprising:

canceling the atrial pacing pulse and reverting to the A-A interval if a ventricular event is sensed prior to the atrial pacing pulse.

3. The method of claim 1, further comprising:

initiating a second AV interval timer upon delivery of the atrial pace;

delivering a ventricular pace at the expiration of the second AV interval timer unless inhibited by a sensed ventricular event.

4. The method of claim 3, wherein the first and second AV intervals have the same duration.

5. The method of claim 1, wherein establishing the A-A interval includes measuring intervals between sensed intrinsic atrial events.

6. The method of claim 1, wherein establishing the A-A interval includes identifying an atrial escape interval.

7. The method of claim 1, wherein the first AV interval timer has a duration determined by patient specific intrinisic AV conduction time.

8. The method of claim 7, wherein the first AV interval timer is an average of AV conduction times over a plurality of cardiac cycles.

9. The method of claim 7, wherein then patient specific AV conduction times are correlated to cardiac rate.

10. An implantable medical device comprising:

means for operating an implantable medical device (IMD) according to a ventricular pacing protocol (VPP) wherein ventricular pacing is precluded in a given cardiac cycle wherein a ventricular event occurred in a cardiac cycle immediately subsequent to the given cardiac cycle;

means for establishing an A-A interval;

means for initiating a first AV interval timer at the initiation of the given cardiac cycle;

means for sensing for ventricular events;

means for scheduling an atrial pacing pulse prior to the termination of the A-A interval if no ventricular event is sensed within the duration of the AV interval timer.

11. The IMD of claim 10, further comprising:

means for canceling the atrial pacing pulse and reverting to the A-A interval if a ventricular event is sensed prior to the atrial pacing pulse.

12. The IMD of claim 10, further comprising:

means for initiating a second AV interval timer upon delivery of the atrial pace;

means for delivering a ventricular pace at the expiration of the second AV interval timer unless inhibited by a sensed ventricular event.

13. The IMD of claim 12, wherein the first and second AV intervals have the same duration.

14. The IMD of claim 10, wherein the first AV interval timer has a duration determined by patient specific intrinisic AV conduction time.

15. The IMD of claim 14, wherein the first AV interval timer is an average of AV conduction times over a plurality of cardiac cycles.

16. The IMD of claim 14, wherein then patient specific AV conduction times are correlated to cardiac rate.

17. A computer readable medium having instructions that when executed on a processor of an implantable medical device have cardiac pacing capabilities cause the IMD to:

establish an A-A interval for a first cardiac cycle;

initiate an AV interval timer concurrent with the initiation of the A-A interval;

sense for a conducted ventricular event; and

schedule an atrial pace to shorten the A-A interval if no conducted ventricular event occurs prior to the expiration of the AV interval timer.

18. The computer readable medium of claim 17, wherein the instruction further cause the processor to:

cancel the atrial pace that shortens the A-A interval if a ventricular event is sensed prior to delivery of the atrial pace.

19. The computer readable medium of claim 17, wherein the instruction further cause the processor to:

initiate an AV interval approximately equal in duration to the AV interval timer concurrent with the atrial pace that shortens the A-A interval; and

deliver a ventricular pacing pulse at the expiration of the AV interval, unless inhibited by a sensed ventricular event.

20. The computer readable medium of claim 17, wherein the AV interval timer has a duration determined by patient specific intrinisic AV conduction times.