Pacing mode event classification with rate smoothing and increased ventricular sensing

• US 7,502,646 B2
• Filed: 07/31/2006
• Issued: 03/10/2009
• Est. Priority Date: 07/31/2006
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Belk, Paul A., Sheldon, Todd J., Betzold, Robert A., Sweeney, Michael O., Hettrick, Douglas A., Stanslaski, Scott R.
• Primary Examiner(s): Evanisko; George R
• Assistant Examiner(s): PATTON, AMANDA K
• Application Number:
  US11/461,141
• Publication Number:
  US 20080027490A1
• Time in Patent Office: 953 Days
• Field of Search: 607/9, 607/14
• US Class Current: 607/9
• CPC Class Codes: A61N 1/368 comprising more than one electrode co-operating with different heart regions A61N1/3622, A61N1/3627 take precedence

Abstract

An implantable medical device operates according to a ventricular pacing protocol (VPP) that precludes ventricular pacing in any cardiac cycle where a sensed ventricular event has occurred in the preceding cycle. Improved ventricular sensing, detection and classification is provided.

Claims

1. A method comprising:

operating an implantable medical device (IMD) according to a ventricular pacing protocol (VPP) wherein a sensed ventricular event in a first cardiac cycle precludes cardiac pacing in a second cardiac cycle immediately subsequent to the first cardiac cycle;

initiating a first post atrial ventricular blanking (PAVB) interval following a first atrial pacing pulse under a first condition;

sensing an electrical signal and providing a first sensed indicator representative of cardiac activity;

accelerating the first cardiac cycle by delivering a second atrial pacing pulse to terminate the first cardiac cycle early in response to the first sensed indicator;

initiating a second PAVB following the first atrial pacing pulse under a second condition, wherein the first PAVB is shorter in duration than the second PAVB; and

providing a crosstalk window subsequent to the atrial pacing pulse during which time sensing is permitted on a ventricular channel and events sensed during the crosstalk window are evaluated according to a feed forward protocol.

2. The method of claim 1, wherein the first condition is when a ventricular pacing pulse has not been provided within a first predetermined interval prior to the atrial pacing and the second condition is when a ventricular pacing pulse has been provided within the first predetermined interval prior to the atrial pacing pulse.

3. The method of claim 2, wherein the feed forward protocol classifies a current event sensed during the crosstalk window as a PVC unless a predetermined number of immediately preceding cardiac cycles each contained a ventricular event sensed during their respective crosstalk windows in which case the current event is classified as crosstalk.

4. The method of claim 3, wherein a PVC is considered a sensed ventricular event for the VPP and precludes ventricular pacing in the next cardiac cycle.

5. The method of claim 2, wherein the first sensed indicator is a premature ventricular contraction (PVC).

6. The method of claim 2, wherein the first PAVB is about 8.5 ms and the second PAVB is about 30 ms.

7. The method of claim 2, wherein the first sensed indicator is an expiration of an AV interval timer.

8. The method of claim 7, further comprising:

initiating the second cardiac cycle with delivery of the second atrial pacing pulse so that ventricular pacing is permitted in the second cardiac cycle; and

initiating a paced AV (PAV) interval timer having a duration expected to permit intrinsic conduction to occur and to deliver a ventricular pacing pulse upon termination of the PAV if no ventricular event has been sensed prior to termination of the PAV.

9. The method of claim 5, further comprising:

modifying atrial interval timing over a plurality of cardiac cycles to return a heart rate to a pre-acceleration rate.

10. An implantable medical device (IMD) comprising:

a processor;

a pulse generator in communication with the processor for selectively providing cardiac pacing stimuli;

a lead system operably coupled to the pulse generator and the processor to deliver the cardiac pacing stimuli and to sense an electrical signal and provide a first sensed indicator representative of the cardiac data, wherein the lead system includes sensing means for sensing the electrical signal;

a ventricular pacing protocol (VPP) module operably coupled to the processor and configured to receive the first sensed indicator indicative of a sensed ventricular event in a first cardiac cycle and to preclude cardiac pacing in a second cardiac cycle immediately subsequent to the first cardiac cycle;

a pacing control module coupled with the processor and configured to initiate a first post atrial ventricular blanking period (PAVB) following an atrial pacing pulse if a first condition is met and initiate a second PAVB, longer in duration than the first PAVB, if a second condition is met and to run a crosstalk window during which sensed ventricular events are classified as a PVC unless a predetermined number of immediately preceding cardiac cycles each contained a ventricular event sensed during their respective crosstalk windows in which case the current event is classified as crosstalk; and

a VPP rate smoothing module configured to deliver a second atrial pacing pulse following the first PAVB to terminate a current cardiac cycle early in response to the first sensed indicator.

11. The IMD of claim 10, wherein the first condition is when a ventricular pacing pulse has not been provided within a first predetermined interval prior to the atrial pacing and the second condition is when a ventricular pacing pulse has been provided within the first predetermined interval prior to the atrial pacing pulse.

12. The IMD of claim 11 wherein the first sensed indicator is a premature ventricular contraction (PVC).

13. The IMD of claim 11 wherein the first sensed indicator is an expiration of an AV interval timer.

14. An apparatus comprising:

means for operating an implantable medical device (IMD) according to a ventricular pacing protocol (VPP) wherein a sensed ventricular event in a first cardiac cycle precludes cardiac pacing in a second cardiac cycle immediately subsequent to the first cardiac cycle;

means for initiating a first post atrial ventricular blanking (PAVB) interval following an atrial pacing pulse under a first condition;

means for sensing an electrical signal and providing a fist sensed indicator representative of cardiac activity;

means for initiating a second PAVB following the atrial pacing pulse under a second condition, wherein the first PAVB is shorter in duration than the second PAVB;

means for accelerating the first cardiac cycle by delivering a second atrial pacing pulse to terminate the first cardiac cycle early in response to the first sensed indicator; and

means for providing a crosstalk window subsequent to the atrial pacing pulse during which time sensing is permitted on a ventricular channel and events sensed during the crosstalk window are evaluated according to a feed forward protocol.

15. The apparatus of claim 14, wherein the first condition is when a ventricular pacing pulse has not been provided within a first predetermined interval prior to the atrial pacing and the second condition is when a ventricular pacing pulse has been provided within the first predetermined interval prior to the atrial pacing pulse.

16. The apparatus of claim 15, wherein the feed forward protocol classifies a current event sensed during the crosstalk window as a PVC unless a predetermined number of immediately preceding cardiac cycles each contained a ventricular event sensed during their respective crosstalk windows in which case the current event is classified as crosstalk.

17. The apparatus of claim 16, wherein a PVC is considered a sensed ventricular event for the VPP and precludes ventricular pacing in the next cardiac cycle.

18. The apparatus of claim 16, wherein the predetermined number of immediately preceding cardiac cycles is one.

19. The apparatus of claim 16, wherein the first PAVB is about 8.5 ms and the second PAVB is about 30 ms.

20. The apparatus of claim 15, wherein the first sensed indicator is a premature ventricular contraction (PVC).

21. The apparatus of claim 15, wherein the first sensed indicator is an expiration of an AV interval timer.

22. The apparatus of claim 15, further comprising:

means for initiating the second cardiac cycle with delivery of the second atrial pacing pulse so that ventricular pacing is permitted in the second cardiac cycle; and

means for initiating a paced AV (PAV) interval timer having a duration expected to permit intrinsic conduction to occur and to deliver a ventricular pacing pulse upon termination of the PAV if no ventricular event has been sensed prior to termination of the PAV.