METHODS AND DEVICES INVOLVING AUTOMATIC ATRIAL BLANKING

• US 20100023083A1
• Filed: 07/22/2008
• Published: 01/28/2010
• Est. Priority Date: 07/22/2008
• Status: Active Grant

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Inventors: Eisinger, George E., Bornzin, Gene A., Snell, Jeffery D.
• Granted Patent: US 8,126,550 B2
• Time in Patent Office: Days
• US Class Current: 607/27
• CPC Class Codes: A61N 1/3622 comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/3704 Circuits specially adapted therefor, e.g. for sensitivity control

Abstract

During a period of time comprising a plurality of cardiac cycles, a time relationship between ventricular events and atrial detections is established. Based on the relationship, a post-ventricular atrial refractory period is defined. The period includes an absolute atrial refractory period and a segmented relative atrial refractory period, wherein the segmented relative atrial refractory period includes at least one blanking window during which atrial detections of ventricular events have or are likely to occur.

Claims

1. A method comprising:

during a period of time comprising a plurality of cardiac cycles, establishing a relationship between ventricular events and atrial detections; and

based on the relationship, defining a post-ventricular atrial refractory period comprising an absolute atrial refractory period and a segmented relative atrial refractory period, wherein the segmented relative atrial refractory period includes at least one blanking window during which atrial detections of ventricular events have or are likely to occur.

2. The method of claim 1 wherein a ventricular event corresponds to one of a ventricular pacing stimulus (V-paced) and an intrinsic ventricular depolarization (R-wave) and an atrial detection corresponds to one of an intrinsic atrial depolarization (P wave), a far-field R wave and a far-field T wave.

3. The method of claim 1 further comprising implementing the post-ventricular atrial refractory period during subsequent cardiac cycles.

4. The method of claim 1 wherein establishing a relationship comprises:

acquiring data related to the timing of ventricular events and atrial detections; and

processing the data to determine if there is a significant time correlation between ventricular events and atrial detections.

5. The method of claim 4 wherein a time correlation is considered significant if a threshold number of atrial detections of ventricular events occur at substantially the same time.

6. The method of claim 5 wherein substantially the same time corresponds to within a time window.

7. The method of claim 4 further comprising monitoring the ventricular rate during the period of time and processing the data only when the ventricular rate is at or below a maximum ventricular rate.

8. The method of claim 4 wherein acquiring occurs during relative atrial refractory periods.

9. The method of claim 4 wherein processing occurs during absolute atrial refractory periods.

10. The method of claim 1 wherein establishing a relationship comprises:

for each of the plurality of cardiac cycles, measuring the time between a ventricular event and each atrial detection within the cardiac cycle;

based on the measured time, associating each atrial detection with one of a plurality of time windows;

for each window, determining a parameter based on the number of times an atrial detection is associated with it; and

comparing the parameter of each time window to a threshold and for each that satisfies the threshold, designating it a blanking window.

11. The method of claim 10 wherein the parameter is a count of the number of times an atrial detection is associated with the time window.

12. The method of claim 10 wherein the parameter is a percentage based on the number of atrial detections associated with the time window and the total number of atrial detection within the time period.

13. The method of claim 10 wherein the parameter is the number of atrial detections within the time window, averaged over the time period.

14. The method of claim 10 wherein the parameter is determined on a beat-by-beat basis.

15. The method of claim 10 wherein the parameter is determined periodically after a plurality of cardiac cycles.

16. The method of claim 10 wherein the ventricular event may be either a paced ventricular event (V-pace) or an intrinsic ventricular event (R-wave) and separate parameters are maintained for each respective ventricular event type.

17. The method of claim 16 wherein designated blanking windows for intrinsic ventricular events are based only on parameters maintained for intrinsic ventricular events.

18. The method of claim 16 wherein designated blanking windows for paced ventricular events are based only on parameters maintained for paced ventricular events.

19. The method of claim 16 wherein designated blanking windows for paced ventricular events are based on parameters maintained for both paced ventricular events and intrinsic ventricular events.

20. A cardiac device comprising:

a ventricular sense channel for sensing ventricular events;

an atrial sense channel for sensing atrial detections; and

a controller connected to the atrial sense channel and the ventricular sense channel and operative to;

during a period of time comprising a plurality of cardiac cycles, establish a relationship between ventricular events and atrial detections; and

based on the relationship, define a post-ventricular atrial refractory period comprising an absolute atrial refractory period and a segmented relative atrial refractory period, wherein the segmented relative atrial refractory period includes at least one blanking window during which atrial detections of ventricular events are likely to occur.

21. A method comprising:

acquiring time data for ventricular events and atrial detections;

processing the acquired time data to establish time relationships between a first ventricular event and each atrial detection that occurs prior to a subsequent ventricular event;

monitoring the time relationships over time to identify atrial detections corresponding to atrial detections of ventricular events; and

for purposes of atrial rate calculations, ignoring atrial detections of ventricular events.

22. The method of claim 21 wherein the time relationships correspond to windows of time.

23. The method of claim 21 wherein monitoring the time relationships over time comprises:

for a particular time relationship, determining a parameter based on the number of times the particular time relationship is established;

comparing the parameter to a threshold; and

if the parameter satisfies the threshold, identifying atrial detections associated with the particular time relationship as an atrial detection of a ventricular event.

24. The method of claim 23 wherein determining a parameter comprises counting the number of times the particular time relationship is established.

25. The method of claim 23 wherein determining a parameter comprises calculating a percentage based on the number of times the particular time relationship is established and the total number of established time relationships.

26. The method of claim 23 wherein determining a parameter comprises calculating an average corresponding to the number of times the particular time relationship is established over a period of time.

27. A cardiac device comprising:

a ventricular sense channel for sensing ventricular events;

an atrial sense channel for sensing atrial detections;

a controller connected to the atrial sense channel and the ventricular sense channel and operative to;

acquire time data for ventricular events and atrial detections;

process the acquired time data to establish time relationships between a first ventricular event and each atrial detection that occurs prior to a subsequent ventricular event;

monitor the time relationships over time to identify atrial detections corresponding to atrial detections of ventricular events; and

ignore atrial detections of ventricular events during atrial rate calculations.