Apparatus and method for pacing mode switching during atrial tachyarrhythmias

• US 7,212,860 B2
• Filed: 11/13/2003
• Issued: 05/01/2007
• Est. Priority Date: 05/21/1999
• Status: Expired due to Fees

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Stahmann, Jeffrey E., Kramer, Andrew P.
• Primary Examiner(s): Pezzuto; Robert E.
• Assistant Examiner(s): Bertram; Eric D.
• Application Number:
  US10/713,556
• Publication Number:
  US 20040172076A1
• Time in Patent Office: 1,265 Days
• Field of Search: 607/4, 607/9, 607/14, 607/15
• US Class Current: 607/14
• CPC Class Codes: A61N 1/3621 for treating or preventing abnormally high heart rate
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/3624 occurring in the atrium, i.e. atrial tachycardia
• 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 1/3684 for stimulating the heart at multiple sites of the ventricle or the atrium
• CPC Class Codes: A61N 1/36843 Bi-ventricular stimulation
• CPC Class Codes: A61N 1/3688 configured for switching the pacing mode, e.g. from AAI to DDD
• CPC Class Codes: A61N 1/395 for treating atrial fibrillation
• CPC Class Codes: A61N 1/39622 Pacing therapy

Abstract

A method for operating a cardiac pacemaker in which the mode of operation of the pacemaker is altered in response to detecting an episode of atrial tachycardia. In accordance with the invention, the pacemaker'"'"'s pacing mode is altered in a manner that attempts to maintain hemodynamic stability during the atrial tachycardia. Such a mode switch is particularly applicable to pacemaker patients suffering from some degree of congestive heart failure.

Claims

1. A method for operating a cardiac pacemaker, comprising:

sensing atrial depolarizations through an atrial sensing channel;

sensing ventricular depolarizations through one or more ventricular sensing channels;

pacing a ventricle in accordance with a particular primary pacing mode;

switching the pacemaker to an atrial fibrillation pacing mode upon detection of an atrial tachyarrhythmia, wherein the atrial fibrillation mode includes ventricular resynchronization pacing and adjustment of a ventricular escape interval in order to regularize the rate at which ventricular beats occur; and

,

adjusting the ventricular escape interval in the atrial fibrillation pacing mode by increasing the ventricular escape interval after each ventricular pace is delivered and decreasing the ventricular escape interval after each ventricular sense.

2. The method of claim 1 wherein the adjustment of the ventricular escape interval is based on a previous value of the ventricular escape interval and a measured intrinsic ventricular rate.

3. The method of claim 1 wherein the adjustment of the ventricular escape interval is performed by increasing the ventricular escape interval after each ventricular pace is delivered and decreasing the ventricular escape interval after each ventricular sense by computing a weighted average of a previous value of the ventricular escape interval and an RR interval, where the RR interval is the interval between the ventricular sense and the preceding ventricular sense or pace.

4. The method of claim 1 wherein the ventricular resynchronization pacing is biventricular pacing with a selected biventricular offset interval.

5. The method of claim 4 wherein the adjustment of the ventricular escape interval is based on a previous value of the ventricular escape interval and a measured intrinsic ventricular rate which increases the ventricular escape interval after a ventricular pace is delivered and decreases the ventricular escape interval after a ventricular sense.

6. The method of claim 5 wherein the pacemaker is normally operated in a primary pacing mode that includes atrial-triggered ventricular pacing, and wherein switching to an atrial fibrillation mode includes reverting to a non-atrial triggered ventricular pacing mode.

7. The method of claim 5 wherein the primary pacing mode includes ventricular resynchronization pacing which is different from the ventricular resynchronization pacing in the atrial fibrillation mode.

8. The method of claim 5 wherein the primary pacing mode is a single ventricle pacing mode which does not include ventricular resynchronization pacing.

9. A cardiac pacemaker, comprising:

an atrial sensing channel for sensing atrial depolarizations;

a ventricular sensing channel for sensing ventricular depolarizations;

right and left pacing channels for delivering paces to the right and left ventricles;

a controller for controlling the delivery of paces in accordance with a primary pacing mode;

wherein the controller is configured to switch the pacemaker to an atrial fibrillation pacing mode upon detection of an atrial tachyarrhythmia, wherein the atrial fibrillation pacing mode includes ventricular resynchronization pacing and adjustment of a ventricular escape interval in order to regularize the rate at which ventricular beats occur; and

,

wherein the controller is configured to adjust the ventricular escape interval in the atrial fibrillation pacing mode by increasing the ventricular escape interval after each ventricular pace is delivered and decreasing the ventricular escape interval after each ventricular sense.

10. The pacemaker of claim 9 wherein the adjustment of the ventricular escape interval is based on a previous value of the ventricular escape interval and a measured intrinsic ventricular rate.

11. The pacemaker of claim 9 wherein the adjustment of the ventricular escape interval is performed by increasing the ventricular escape interval after each ventricular pace is delivered and decreasing the ventricular escape interval after each ventricular sense by computing a weighted average of a previous value of the ventricular escape interval and an RR interval, where the RR interval is the interval between the ventricular sense and the preceding ventricular sense or pace.

12. The pacemaker of claim 9 wherein the ventricular resynchronization pacing is biventricular pacing with a selected biventricular offset interval.

13. The pacemaker of claim 12 wherein the adjustment of the ventricular escape interval is based on a previous value of the ventricular escape interval and a measured intrinsic ventricular rate which increases the ventricular escape interval after a ventricular pace is delivered and decreases the ventricular escape interval after a ventricular sense.

14. The pacemaker of claim 13 wherein the pacemaker is normally operated in a primary pacing mode that includes atrial-triggered ventricular pacing, and wherein switching to an atrial fibrillation mode includes reverting to a non-atrial triggered ventricular pacing mode.

15. The pacemaker of claim 13 wherein the primary pacing mode includes ventricular resynchronization pacing which is different from the ventricular resynchronization pacing in the atrial fibrillation mode.

16. The pacemaker of claim 13 wherein the primary pacing mode is a single ventricle pacing mode which does not include ventricular resynchronization pacing.

17. The pacemaker of claim 9 wherein the adjustment of the ventricular escape interval is performed by increasing the ventricular escape interval after each ventricular pace is delivered by an amount depending upon a previous value of the ventricular escape interval.

18. The pacemaker of claim 17 wherein the adjustment of the ventricular escape interval is performed by increasing the ventricular escape interval after each ventricular pace is delivered by multiplying a previous value of the ventricular escape interval by a specified coefficient.

19. The method of claim 9 wherein the adjustment of the ventricular escape interval is performed by increasing the ventricular escape interval after each ventricular pace is delivered by an amount depending upon a previous value of the ventricular escape interval.

20. The method of claim 19 wherein the adjustment of the ventricular escape interval is performed by increasing the ventricular escape interval after each ventricular pace is delivered by multiplying a previous value of the ventricular escape interval by a specified coefficient.