Apparatus and method for ventricular rate regularization

• US 7,181,278 B2
• Filed: 03/20/2003
• Issued: 02/20/2007
• Est. Priority Date: 05/21/1999
• Status: Expired due to Term

• 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): DROESCH, KRISTEN L
• Application Number:
  US10/394,497
• Publication Number:
  US 20030233131A1
• Time in Patent Office: 1,433 Days
• Field of Search: None
• US Class Current: 607/9
• 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 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/365 controlled by a physiological parameter, e.g. heart potential evoked response A61N1/371
• 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
• 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 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371
• CPC Class Codes: A61N 1/395 for treating atrial fibrillation
• CPC Class Codes: A61N 1/39622 Pacing therapy
• CPC Class Codes: A61N 1/3987 characterised by the timing or triggering of the shock

Abstract

A cardiac rhythm management device which employs pacing therapy to regularize the ventricular rhythm. Such ventricular rate regularization may be employed within bradycardia pacemakers, ventricular resynchronization devices, or implantable cardioverter/defibrillators.

Claims

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

delivering paces to both ventricles with one ventricle designated as a rate chamber and the other ventricle as a synchronized chamber;

sensing depolarizations from the rate chamber;

delivering a rate chamber pace upon expiration of a ventricular escape interval that is reset by a rate chamber sense, the reciprocal of the ventricular escape interval being the lower rate limit;

pacing the synchronized chamber in accordance with a synchronized pacing mode such that a synchronized chamber pace is delivered at a specified pacing instant defined with respect to expiration of the ventricular escape interval;

measuring an R—

R interval associated with each rate chamber sense, an R—

R interval being the time between a rate chamber sense and a preceding rate chamber sense or pace, with the reciprocal of the R—

R interval thus being the measured intrinsic ventricular rate; and

,

delivering ventricular rate regularization therapy by adjusting the ventricular escape interval in accordance with a measured R—

R interval so that the lower rate limit is adjusted to move toward the measured intrinsic ventricular rate.

2. The method of claim 1 further comprising sensing the rate chamber.

3. The method of claim 1 further comprising:

sensing an atrium;

delivering an atrial pace upon expiration of an atrial escape interval and to deliver a ventricular pace upon expiration of an atrio-ventricular escape interval initiated by an atrial sense.

4. The method of claim 1 further comprising:

detecting ventricular fibrillation based on the sensed ventricular activity; and

applying a ventricular defibrillation shock after detection of fibrillation.

5. The method of claim 4 further comprising initiating ventricular regularization therapy upon detection of ventricular fibrillation.

6. The method of claim 1 further comprising:

detecting atrial fibrillation based on the sensed atrial activity; and

a applying an atrial defibrillation shock after detection of atrial fibrillation.

7. The method of claim 6 further comprising delivering ventricular rate regularization therapy for a specified period of time upon detection of an irregular ventricular tachycardia.

8. The method of claim 1 further comprising:

increasing the ventricular escape interval upon delivery of a ventricular pace; and

,

decreasing the ventricular escape interval upon occurrence of a ventricular sense in accordance with the measured R—

R interval.

9. The method of claim 1 further comprising adjusting the ventricular escape interval toward a value corresponding to a base lower rate limit after a ventricular pace.

10. The method of claim 1 further comprising adjusting the ventricular escape interval by computing a weighted average of the measured R—

R interval multiplied by a scaling factor and the previous value of the ventricular escape interval after each ventricular sense, and wherein the ventricular escape interval is adjusted by multiplying the escape interval by a decay coefficient after a ventricular pace.

11. A cardiac rhythm management device, comprising:

ventricular pacing channels for delivering paces to both ventricles with one ventricle designated as a rate chamber and the other ventricle as a synchronized chamber;

a sensing channel configurable for sensing depolarizations from the rate chamber;

a controller for controlling the delivery of paces by the ventricular pacing channels;

wherein the controller is configured to deliver a rate chamber pace upon expiration of a ventricular escape interval that is reset by a rate chamber sense, the reciprocal of the ventricular escape interval being the lower rate limit;

wherein the controller is programmed to pace the synchronized chamber in accordance with a synchronized pacing mode such that a synchronized chamber pace is delivered at a specified pacing instant defined with respect to expiration of the ventricular escape interval;

wherein the controller is configured to measure an R—

R interval associated with each rate chamber sense, an R—

R interval being the time between a rate chamber sense and a preceding rate chamber sense or pace, with the reciprocal of the R—

R interval thus being the measured intrinsic ventricular rate; and

,

wherein the controller is further configured to deliver ventricular rate regularization therapy by adjusting the ventricular escape interval in accordance with a measured R—

R interval so that the lower rate limit is adjusted to move toward the measured intrinsic ventricular rate.

12. The device of claim 11

further comprising a sensing channel configurable for sensing the rate chamber.

13. The device of claim 11 further comprising:

atrial sensing and pacing channels;

wherein the controller is configured to deliver an atrial pace upon expiration of an atrial escape interval and to deliver a ventricular pace upon expiration of an atrio-ventricular escape interval initiated by an atrial sense.

14. The device of claim 11 further comprising:

a fibrillation detector for detecting ventricular fibrillation based on the sensed ventricular activity; and

a shock pulse generator for applying a ventricular defibrillation shock after detection of fibrillation.

15. The device of claim 14 wherein the controller is configured to deliver ventricular rate regularization therapy for a specified period of time upon detection of an irregular ventricular tachycardia.

16. The device of claim 11 further comprising:

an atrial fibrillation detector for detecting atrial fibrillation based on the sensed atrial activity; and

an atrial shock pulse generator for applying an atrial defibrillation shock after detection of atrial fibrillation, the shock pulse generator timing the shock based on one or more of the ventricular depolarizations.

17. The device of claim 16 further comprising:

a fibrillation detector for detecting ventricular fibrillation based on the sensed ventricular activity; and

a shock pulse generator for applying a ventricular defibrillation shock after detection of fibrillation.

18. The device of claim 16 wherein the controller is configured to initiate ventricular regularization therapy upon detection of atrial fibrillation.

19. The device of claim 11 further comprising:

an R—

R interval detector;

a ventricular escape interval timer;

a filter for increasing the ventricular escape interval upon delivery of a ventricular pace; and

,

a filter for decreasing the ventricular escape interval upon occurrence of a ventricular sense in accordance with the measured R—

R interval.

20. The device of claim 11 wherein the controller is configured to adjust the ventricular escape interval toward a value corresponding to a base lower rate limit after a ventricular pace.

21. The device of claim 11 wherein the controller is configured to adjust the ventricular escape interval by computing a weighted average of the measured R—

R interval multiplied by a scaling factor and the previous value of the ventricular escape interval after each ventricular sense, and wherein the ventricular escape interval is adjusted by multiplying the escape interval by a decay coefficient after a ventricular pace.

22. A cardiac rhythm management device, comprising:

a sensing channel configurable for sensing depolarizations from a right ventricle;

ventricular pacing channels for delivering paces to both right and left ventricles;

a controller for controlling the delivery of paces by the ventricular pacing channels;

wherein the controller is configured to deliver a right ventricular pace upon expiration of a ventricular escape interval that is reset by a right ventricular sense, the reciprocal of the ventricular escape interval being the lower rate limit;

wherein the controller is programmed to pace the left ventricle in accordance with a synchronized pacing mode such that a left ventricular pace is delivered at a specified pacing instant defined with respect to expiration of the ventricular escape interval;

wherein the controller is configured to measure an R—

R interval associated with each right ventricular sense, an R—

R interval being the time between a right ventricular sense and a preceding right ventricular sense or pace, with the reciprocal of the R—

R interval thus being the measured intrinsic ventricular rate; and

,

wherein the controller is further configured to deliver ventricular rate regularization therapy by adjusting the ventricular escape interval in accordance with a measured R—

R interval so that the lower rate limit is adjusted to move toward the measured intrinsic ventricular rate.

23. The device of claim 22

further comprising a sensing channel configurable for sensing the left ventricle.

24. The device of claim 22 further comprising:

atrial sensing and pacing channels; and

,

wherein the controller is configured to deliver an atrial pace upon expiration of an atrial escape interval and to deliver a ventricular pace upon expiration of an atrio-ventricular escape interval initiated by an atrial sense.

25. The device of claim 22 further comprising:

an R—

R interval detector;

a ventricular escape interval timer;

a filter for increasing the ventricular escape interval upon delivery of a ventricular pace; and

,

a filter for decreasing the ventricular escape interval upon occurrence of a ventricular sense in accordance with the measured R—

R interval.

26. The device of claim 22 wherein the controller is configured to adjust the ventricular escape interval by computing a weighted average of the measured R—

R interval multiplied by a scaling factor and the previous value of the ventricular escape interval after each ventricular sense, and wherein the ventricular escape interval is adjusted by multiplying the escape interval by a decay coefficient after a ventricular pace.