Electrogram morphology-based CRT optimization

• US 20060224198A1
• Filed: 04/01/2005
• Published: 10/05/2006
• Est. Priority Date: 04/01/2005
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Meyer, Scott A., Dong, Yanting, Yu, Yinghong, Ding, Jiang, Daum, Douglas R.
• Granted Patent: US 7,555,340 B2
• Time in Patent Office: Days
• 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
• CPC Class Codes: A61N 1/3682 with a variable atrioventricular delay
• CPC Class Codes: A61N 1/371 Capture, i.e. successful stimulation

Abstract

A method and system are described for determining an optimum atrioventricular delay (AVD) interval and/or ventriculo-ventricular delay (VVD) intervals for delivering ventricular resynchronization pacing in an atrial tracking or atrial sequential pacing mode. Evoked response electrograms recorded at different AVD and VVD intervals are used to determine the extent of paced and intrinsic activation.

Claims

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

delivering paces to both right and left ventricles or to the left ventricle only in accordance with a programmed pacing mode, such that the pace or paces are delivered after a programmed AV delay interval with respect to an atrial event; and

,

determining an optimum AV delay interval by;

recording an evoked response electrogram during a paced cardiac cycle with a short AV delay interval expected to be shorter than the patient'"'"'s intrinsic atrioventricular interval to ensure complete capture of the ventricles;

incrementing the AV delay interval by a predetermined amount and recording an evoked response electrogram during a paced cardiac cycle with the incremented AV delay interval;

comparing the evoked response electrograms recorded with the incremented and short AV delay intervals; and

,

continuing to increment the AV delay interval by the predetermined amount until the evoked response electrogram recorded with the incremented AV delay interval differs from the evoked response electrogram recorded with the short AV delay interval by a specified amount.

2. The method of claim 1 wherein the difference between the evoked response electrograms recorded with the short and incremented AV delay intervals is determined by performing a cross-correlation between the two electrograms and comparing the resulting cross-correlation coefficient to a specified threshold value.

3. The method of claim 1 wherein the difference between the evoked response electrograms recorded with the short and incremented AV delay intervals is determined by extracting a feature from each of the two electrograms and comparing the difference between the extracted features with a specified threshold value.

4. The method of claim 1 further comprising determining optimum AV delay intervals at a plurality of different pacing pulse energies.

5. The method of claim 1 further comprising determining optimum AV delay intervals at a plurality of different atrial rates.

6. The method of claim 5 further comprising:

using the optimum AV delay intervals as determined at the plurality of atrial rates to form a mapping function which maps particular atrial rates to particular programmed AV delay intervals; and

,

automatically adjusting the programmed AV delay interval according to the mapping function as the atrial rate changes.

7. The method of claim 6 wherein the mapping function is a look-up table.

8. The method of claim 6 wherein the mapping function is a linear function.

9. The method of claim 1 further comprising determining a separate optimum AV delay interval depending upon whether the atrial event is an atrial sense or an atrial pace.

10. The method of claim 1 further comprising determining an optimum VV delay interval for biventricular pacing by:

recording an evoked response electrogram during a biventricular paced cardiac cycle with the determined optimum AV delay interval with a short VV delay interval expected to be short enough to produce biventricular capture;

incrementing the VV delay interval by a predetermined amount and recording an evoked response electrogram during a paced cardiac cycle with the incremented VV delay interval;

comparing the evoked response electrograms recorded with the incremented and short VV delay intervals; and

,

continuing to increment the VV delay interval by the predetermined amount until the evoked response electrogram recorded with the incremented VV delay interval differs from the evoked response electrogram recorded with the short VV delay interval by a specified amount.

11. The method of claim 10 further comprising determining optimum VV delay intervals for multiple pacing sites in the left ventricle.

12. The method of claim 1 further comprising selecting a sensing vector for generating evoked response electrograms which produces the greatest morphology difference between electrograms of fusion beats and electrograms of purely paced beats.

13. A cardiac rhythm management device, comprising:

pacing channels through which paces may be delivered to both right and left ventricles;

one or more sensing channels for generating an electrogram signal;

a controller programmed to deliver biventricular or left ventricle-only paces in accordance with a programmed pacing mode such that the pace or paces are delivered after a programmed AV delay interval with respect to an atrial event;

wherein the controller is programmed to determine an optimum AV delay interval by;

recording an evoked response electrogram during a paced cardiac cycle with a short AV delay interval which is expected to be shorter than the patient'"'"'s intrinsic atrioventricular interval;

incrementing the AV delay interval by a predetermined amount and recording an evoked response electrogram during a paced cardiac cycle with the incremented AV delay interval;

comparing the evoked response electrograms recorded with the incremented and short AV delay intervals; and

,

continuing to increment the AV delay interval by the predetermined amount until the evoked response electrogram recorded with the incremented AV delay interval differs from the evoked response electrogram recorded with the short AV delay interval by a specified amount.

14. The device of claim 13 wherein the difference between the evoked response electrograms recorded with the short and incremented AV delay intervals is determined by performing a cross-correlation between the two electrograms and comparing the resulting cross-correlation coefficient to a specified threshold value.

15. The device of claim 13 wherein the difference between the evoked response electrograms recorded with the short and incremented AV delay intervals is determined by extracting a feature from each of the two electrograms and comparing the difference between the extracted features with a specified threshold value.

16. The device of claim 13 wherein the controller is further programmed to determine optimum AV delay intervals at a plurality of different pacing pulse energies.

17. The device of claim 13 wherein the controller is further programmed to determine optimum AV delay intervals at a plurality of different atrial rates.

18. The device of claim 17 wherein the controller is further programmed to:

use the optimum AV delay intervals as determined at the plurality of atrial rates to form a mapping function which maps particular atrial rates to particular programmed AV delay intervals; and

,

automatically adjust the programmed AV delay interval according to the mapping function as the atrial rate changes.

19. The device of claim 18 wherein the mapping function is a look-up table.

20. The device of claim 18 wherein the mapping function is a linear function.

21. The device of claim 13 wherein the controller is further programmed to determine a separate optimum AV delay interval depending upon whether the atrial event is an atrial sense or an atrial pace.

22. The device of claim 13 wherein the controller is further programmed to determine an optimum VV delay interval for biventricular pacing by:

recording an evoked response electrogram during a biventricular paced cardiac cycle with the determined optimum AV delay interval with a short VV delay interval expected to be short enough to produce biventricular capture;

incrementing the VV delay interval by a predetermined amount and recording an evoked response electrogram during a paced cardiac cycle with the incremented VV delay interval;

comparing the evoked response electrograms recorded with the incremented and short VV delay intervals; and

,

continuing to increment the VV delay interval by the predetermined amount until the evoked response electrogram recorded with the incremented VV delay interval differs from the evoked response electrogram recorded with the short VV delay interval by a specified amount.

23. The device of claim 13 wherein the controller is further programmed to select a sensing vector for generating evoked response electrograms which produces the greatest morphology difference between electrograms of fusion beats and electrograms of purely paced beats.

24. A system, comprising:

an implantable cardiac rhythm management device having pacing channels through which paces may be delivered to both right and left ventricles;

a controller programmed to deliver biventricular or left ventricle-only paces in accordance with a programmed pacing mode such that the pace or paces are delivered after a programmed AV delay interval with respect to an atrial event;

an external programmer in communication with the implantable device which is programmed to determine an optimum AV delay interval by;

recording an evoked response electrogram during a paced cardiac cycle with a short AV delay interval expected to be shorter than the patient'"'"'s intrinsic atrioventricular interval;

incrementing the AV delay interval by a predetermined amount and recording an evoked response electrogram during a paced cardiac cycle with the incremented AV delay interval;

comparing the evoked response electrograms recorded with the incremented and short AV delay intervals; and

,

continuing to increment the AV delay interval by the predetermined amount until the evoked response electrogram recorded with the incremented AV delay interval differs from the evoked response electrogram recorded with the short AV delay interval by a specified amount.

25. The system of claim 24 wherein the difference between the evoked response electrograms recorded with the short and incremented AV delay intervals is determined by performing a cross-correlation between the two electrograms and comparing the resulting cross-correlation coefficient to a specified threshold value.

26. The system of claim 24 wherein the difference between the evoked response electrograms recorded with the short and incremented AV delay intervals is determined by extracting a feature from each of the two electrograms and comparing the difference between the extracted features with a specified threshold value.

27. The system of claim 24 wherein the external programmer is further programmed to determine optimum AV delay intervals at a plurality of different atrial rates.

28. The system of claim 24 wherein the external programmer is further programmed to:

use the optimum AV delay intervals as determined at the plurality of atrial rates to form a mapping function which maps particular atrial rates to particular programmed AV delay intervals; and

,

automatically adjust the programmed AV delay interval according to the mapping function as the atrial rate changes.

29. The system of claim 24 wherein the external programmer is further programmed to determine an optimum VV delay interval for biventricular pacing by:

recording an evoked response electrogram during a biventricular paced cardiac cycle with the determined optimum AV delay interval with a short VV delay interval expected to be short enough to produce biventricular capture;

incrementing the VV delay interval by a predetermined amount and recording an evoked response electrogram during a paced cardiac cycle with the incremented VV delay interval;

comparing the evoked response electrograms recorded with the incremented and short VV delay intervals; and

,

continuing to increment the VV delay interval by the predetermined amount until the evoked response electrogram recorded with the incremented VV delay interval differs from the evoked response electrogram recorded with the short VV delay interval by a specified amount.

30. The system of claim 26 wherein the external programmer is further programmed to select a sensing vector for generating evoked response electrograms which produces the greatest morphology difference between electrograms of fusion beats and electrograms of purely paced beats.

31. A method for operating a cardiac rhythm management device in a patient, comprising:

delivering paces to both right and left ventricles or to the left ventricle only in accordance with a programmed pacing mode, such that the pace or paces are delivered after a programmed AV delay interval with respect to an atrial event; and

,

determining an optimum AV delay interval by;

recording an intrinsic reference electrogram;

incrementing the AV delay interval by a predetermined amount and recording an evoked response electrogram during a paced cardiac cycle with the incremented AV delay interval;

comparing the evoked response electrograms recorded with the incremented AV delay intervals and the reference electrogram; and

,

continuing to decrement the AV delay interval by the predetermined amount until the evoked response electrogram recorded with the decremented AV delay interval differs from the reference electrogram by a specified amount.