Adaptive windowing for cardiac waveform discrimination

• US 20060247696A1
• Filed: 04/28/2005
• Published: 11/02/2006
• Est. Priority Date: 04/28/2005
• 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, Stalsberg, Kevin John, Bohn, Derek Daniel, Enrooth, Eric Keith
• Granted Patent: US 7,574,260 B2
• Time in Patent Office: Days
• US Class Current: 607/9
• CPC Class Codes: A61B 5/35 by template matching
• CPC Class Codes: A61B 5/366 Detecting abnormal QRS complex, e.g. widening
• CPC Class Codes: A61B 5/7217 of noise originating from a therapeutic or surgical apparatus, e.g. from a pacemaker
• CPC Class Codes: A61N 1/371 Capture, i.e. successful stimulation

Abstract

Cardiac devices and methods provide adaptation of detection windows used to determine a cardiac response to pacing. Adapting a detection window involves sensing a cardiac signal indicative of a particular type of cardiac pacing response, and detecting a feature of the sensed cardiac signal. The cardiac response detection window associated with the type of cardiac pacing response is preferentially adjusted based on the location of the detected cardiac feature. Preferential adjustment of the detection window may involve determining a direction of change between the detection window and the detected feature. The detection window may be adapted more aggressively in a more preferred direction and less aggressively in a less preferred direction.

Claims

1. A method for adjusting a detection window used to detect a type of cardiac response, comprising:

sensing a cardiac signal associated with the type of cardiac response;

detecting a feature of the sensed cardiac signal; and

preferentially adjusting the detection window based on a location of the detected feature.

2. The method of claim 1, wherein preferentially adjusting the detection window comprises:

determining a direction of change between the detection window and the location of the detected feature; and

preferentially adjusting the detection window based on the direction of change.

3. The method of claim 2, wherein preferentially adjusting the detection window comprises:

adjusting the detection window more aggressively in a more preferred direction of change; and

adjusting the detection window less aggressively in a less preferred direction of change.

4. The method of claim 1, wherein preferentially adjusting the detection window based on the location of the detected feature comprises determining whether the detected feature is used to modify the detection window based on the location of the detected feature.

5. The method of claim 4, wherein determining if the detected feature is used to modify the detection window comprises determining a relationship between the location of the detected feature and one or more detection window limits.

6. The method of claim 1, wherein preferentially adjusting the detection window comprises compressing the detection window against a detection window limit.

7. The method of claim 1, wherein the type of cardiac response comprises a captured beat and the detection window comprises a capture detection window.

8. The method of claim 1, wherein the type of cardiac response comprises a fusion beat and the detection window comprises a fusion detection window.

9. The method of claim 1, wherein the type of cardiac response comprises a non-captured beat with intrinsic activation and the detection window comprises an intrinsic detection window.

10. The method of claim 1, wherein the type of cardiac response comprises a noisy signal and the detection window comprises a noise detection window.

11. The method of claim 1, wherein the detection window has dimensions of time and amplitude and wherein detecting the feature comprises detecting the feature having an amplitude coordinate and a time coordinate.

12. The method of claim 1, wherein preferentially adjusting the at least one detection window comprises preferentially adjusting a location of the detection window.

13. The method of claim 1, wherein preferentially adjusting the detection window comprises preferentially adjusting a boundary of the detection window.

14. The method of claim 1, wherein preferentially adjusting the detection window comprises preferentially adjusting an area of the detection window.

15. A system, comprising:

a sensing system configured to sense a cardiac signal following a pacing pulse delivered to a heart, the cardiac signal associated with a type of cardiac response to the pacing pulse; and

a processor coupled to the sensing system, the processor configured to provide a detection window for detecting the type of cardiac response, the processor further configured to detect a feature of the cardiac signal, and to preferentially adjust the detection window based on a location of the cardiac signal feature.

16. The system of claim 15, wherein the processor is configured to determine a direction of change between the detection window and the location of the detected feature and to preferentially adjust the detection window based on the direction of change.

17. The system of claim 16, wherein the processor is configured to adjust the detection window more aggressively in a more preferred direction of change and to adjust the detection window less aggressively in a less preferred direction of change.

18. The system of claim 15, wherein the detection window has dimensions of amplitude and time and the location of the detected feature has coordinates of amplitude and time.

19. The system of claim 15, wherein the one or more detection window has constraints, the detection window constraints comprising one or more of amplitude limits and time limits.

20. The system of claim 15, wherein the processor is configured to preferentially adjust a location of the detection window.

21. The system of claim 15, wherein the processor is configured to preferentially adjust a boundary of the detection window.

22. The system of claim 15, wherein the processor is configured to compress the detection window against a detection window limit.

23. The system of claim 15, wherein the processor is configured to determine whether the detected feature is used to modify the detection window based on the location of the detected feature.

24. A system for adjusting a detection window used to detect a type of cardiac response, comprising:

a detector configured to detect a feature of a cardiac signal associated with the type of cardiac response; and

means for preferentially adjusting the detection window based on a location of the detected feature.

25. The system of claim 24, further comprising:

means for determining a direction of change between the detection window and the location of the detected feature; and

means for preferentially adjusting the detection window based on the direction of change.

26. The system of claim 24, further comprising:

means for adjusting the detection window more aggressively in a more preferred direction of change; and

means for adjusting the detection window less aggressively in a less preferred direction of change.

27. The system of claim 24, further comprising means for determining whether the detected feature is used to modify the detection window based on the location of the detected feature.

28. The system of claim 24, further comprising means for compressing the detection window against a detection window limit.