SYSTEMS AND METHODS FOR PREVENTING, DETECTING, AND TERMINATING PACEMAKER MEDIATED TACHYCARDIA IN BIVENTRICULAR IMPLANTABLE CARDIAC STIMULATION SYSTEMS

• US 20070244521A1
• Filed: 04/11/2007
• Published: 10/18/2007
• Est. Priority Date: 02/14/2002
• Status: Active Grant

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories Incorporated)
• Inventors: Kroll, Mark, Bornzin, Gene
• Granted Patent: US 7,813,798 B2
• Time in Patent Office: Days
• US Class Current: 607/9
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• 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 1/3684 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 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion

Abstract

Various techniques are described for preventing pacemaker mediated tachycardia (PMT) within biventricular pacing systems and for detecting and terminating PMT should it nevertheless arise. In a first prevention technique, refractory periods applied to the atrial channel are synchronized to begin with a second of a pair of ventricular pacing pulses to more effectively prevent T-wave oversensing on the atrial channel. In a second prevention technique, the sensitivity of the atrial channel is reduced during T-waves also to prevent T-wave oversensing. In a third prevention technique, template matching is performed on the ventricular channels to prevent T-wave oversensing. In a fourth prevention technique, T-wave detection windows are applied to both the ventricular and atrial channels subsequent to any paced or sensed events. In a first detection technique, PMT is detected based upon a degree of variation within V-pulse to P-wave pacing intervals. In a second detection technique, PMT is detected based upon a degree variation within ventricular pacing intervals. In either case, if the degree of variation is too low, indicative of PMT, ventricular refractory periods are expanded to terminate the PMT.

Claims

1. In an implantable cardiac stimulation device having a biventricular pacing system and a pacemaker mediated tachycardia (PMT) prevention system, a method comprising:

delivering a pair of biventricular pacing pulses to left and right ventricles of a heart using the biventricular pacing system, the pair of biventricular pacing pulses comprising a first ventricular pacing pulse and a second ventricular pacing pulse; and

triggering a post ventricular atrial refractory period (PVARP) upon delivery of the second ventricular pacing pulse to prevent onset of PMT.

2. The method of claim 1 wherein triggering a PVARP upon delivery of the second ventricular pacing pulse comprises:

suspending sensing on an atrial sensing channel for a duration of the PVARP; and

after the duration of the PVARP has expired, resuming processing of the atrial sensing channel.

3. The method of claim 1 wherein a duration of the PVARP comprises:

deactivating atrial sense amplifiers during an atrial blanking period; and

activating the atrial sense amplifiers to sense events on the atrial sensing channel during an atrial refractory period, the implantable cardiac stimulation device not responding to sensed events on the atrial sensing channel during the atrial refractory period.

4. The method of claim 1 wherein a duration of the PVARP more effectively covers both a far field T-wave associated with the first ventricular pacing pulse and a far field T-wave associated with the second ventricular pacing pulse on an atrial sensing channel by triggering the PVARP upon delivery of the second ventricular pacing pulse, and wherein the PVARP may expire by the time the T-wave associated with the second ventricular pacing pulse is generated and propagated to atrial sensing locations if the PVARP is triggered upon delivery of the first ventricular pacing pulse.

5. The method of claim 1 wherein a duration of the PVARP comprises a standard duration to avoid improperly covering a subsequent true P-wave during high heart rates.

6. The method of claim 1 wherein delivering a pair of biventricular pacing pulses to the left and right ventricles of the heart comprises timing the delivery of the first ventricular pacing pulse and the second ventricular pacing pulse to optimally synchronize contraction between the left and right ventricles.

7. In an implantable cardiac stimulation device having a biventricular pacing system and a pacemaker mediated tachycardia (PMT) detection and termination system, a method comprising:

determining a sequence for delivery of a pair of biventricular pacing pulses to a first ventricle and a second ventricle using the biventricular pacing system, the pair of biventricular pacing pulses comprising a first ventricular pacing pulse to the first ventricle and a second ventricular pacing pulse to the second ventricle;

delivering the first ventricular pacing pulse to the first ventricle in accordance with the sequence determined by the biventricular pacing system;

delivering the second ventricular pacing pulse to the second ventricle in accordance with the sequence determined by the biventricular pacing system; and

triggering a post ventricular atrial refractory period (PVARP) upon delivery of the second ventricular pacing pulse using the PMT detection and termination system to prevent onset of PMT.

8. The method of claim 7 wherein triggering a PVARP upon delivery of the second ventricular pacing pulse comprises:

suspending sensing on an atrial sensing channel for a duration of the PVARP; and

after the duration of the PVARP has expired, resuming processing of the atrial sensing channel.

9. The method of claim 7 wherein a duration of the PVARP comprises:

deactivating atrial sense amplifiers during an atrial blanking period; and

activating the atrial sense amplifiers for sensing events on an atrial sensing channel during an atrial refractory period, the implantable cardiac stimulation device not responding to sensed events on the atrial sensing channel during the atrial refractory period.

10. The method of claim 7 wherein a duration of the PVARP more effectively covers both a far field T-wave associated with the first ventricular pacing pulse and a far field T-wave associated with the second ventricular pacing pulse by triggering the PVARP upon delivery of the second ventricular pacing pulse, and wherein the PVARP may expire by the time the T-wave associated with the second ventricular pacing pulse is generated and propagated to atrial sensing locations if the PVARP is triggered upon delivery of the first ventricular pacing pulse.

11. The method of claim 7 wherein a duration of the PVARP comprises a standard duration to avoid improperly covering a subsequent true P-wave during high heart rates.

12. The method of claim 7 wherein delivering a pair of biventricular pacing pulses to the left and right ventricles of the heart comprises timing the delivery of the first ventricular pacing pulse and the second ventricular pacing pulse to optimally synchronize contraction between the left and right ventricles.

13. An implantable cardiac stimulation device comprising:

a pulse generator delivering a pair of biventricular pacing pulses to left and right ventricles of a heart, the pair of biventricular pacing pulses comprising a first ventricular pacing pulse and a second ventricular pacing pulse;

an atrial sensing channel sensing atrial activity;

a controller that is operative to control the pulse generator to deliver the pair of biventricular pacing pulses; and

a pacemaker mediated tachycardia (PMT) prevention system to trigger a post ventricular atrial refractory period (PVARP) upon delivery of the second ventricular pacing pulse to prevent onset of PMT.

14. The device of claim 13 wherein the PMT prevention system suspends sensing on the atrial sensing channel for a duration of the PVARP and resumes processing of the atrial sensing channel after the duration of the PVARP has expired.

15. The device of claim 13 wherein a duration of the PVARP comprises:

an atrial blanking period during which atrial sense amplifiers are deactivated; and

an atrial refractory period during which the atrial sense amplifiers are active for sensing events on the atrial sense channel and during which the cardiac stimulation device is not responsive to sensed events on the atrial sensing channel.

16. The device of claim 13 wherein a duration of the PVARP more effectively covers both a far field T-wave associated with the first ventricular pacing pulse and a far field T-wave associated with the second ventricular pacing pulse by triggering the PVARP upon delivery of the second ventricular pacing pulse, and wherein the PVARP may expire by the time the T-wave associated with the second ventricular pacing pulse is generated and propagated to atrial sensing locations if the PVARP is triggered upon delivery of the first ventricular pacing pulse.

17. The device of claim 13 wherein a duration of the PVARP comprises a standard duration to avoid improperly covering a subsequent true P-wave during high heart rates.

18. The device of claim 13 wherein the pulse generator delivering a pair of biventricular pacing pulses to the left and right ventricles of the heart comprises timing the delivery of the first ventricular pacing pulse and the second ventricular pacing pulse to optimally synchronize contraction between the left and right ventricles.

24. The device of claim 13 wherein the biventricular pacing system times the delivery of the first ventricular pacing pulse and the second ventricular pacing pulse to optimally synchronize contraction between the left and right ventricles.

19. An implantable cardiac stimulation device comprising:

a biventricular pacing system determining a sequence for delivery of a pair of pacing pulses to a first ventricle and a second ventricle, the pair of biventricular pacing pulses comprising a first ventricular pacing pulse to the first ventricle and a second ventricular pacing pulse to the second ventricle; and

a pacemaker mediated tachycardia (PMT) detection and termination system triggering a post ventricular atrial refractory period (PVARP) upon delivery of the second ventricular pacing pulse to prevent onset of PMT.

20. The device of claim 19 wherein the PMT detection and termination system suspends sensing on the atrial sensing channel for a duration of the PVARP and resumes processing of the atrial sensing channel after the duration of the PVARP has expired.

21. The device of claim 19 wherein a duration of the PVARP comprises:

an atrial blanking period during which atrial sense amplifiers are deactivated; and

an atrial refractory period during which the atrial sense amplifiers are active for sensing events on the atrial sensing channel and during which the cardiac stimulation device is not responsive to sensed events on the atrial sensing channel.

22. The device of claim 19 wherein a duration of the PVARP more effectively covers both a far field T-wave associated with the first ventricular pacing pulse and a far field T-wave associated with the second ventricular pacing pulse on an atrial sensing channel by triggering the PVARP upon delivery of the second ventricular pacing pulse, and wherein the PVARP may expire by the time the T-wave associated with the second ventricular pacing pulse is generated and propagated to atrial sensing locations if the PVARP is triggered upon delivery of the first ventricular pacing pulse.

23. The device of claim 19 wherein a duration of the PVARP comprises a standard duration to avoid improperly covering a subsequent true P-wave during high heart rates.