Cardiac response classification using retriggerable classification windows

• US 7,774,064 B2
• Filed: 12/12/2003
• Issued: 08/10/2010
• Est. Priority Date: 12/12/2003
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Dong, Yanting, Meyer, Scott A., Maniak, Jeremy, Voegele, John, Birholz, Doug
• Primary Examiner(s): Evanisko; George R
• Assistant Examiner(s): ALTER, ALYSSA MARGO
• Application Number:
  US10/734,599
• Publication Number:
  US 20050131477A1
• Time in Patent Office: 2,433 Days
• Field of Search: 607/9, 607 27- 29, 600/510
• US Class Current: 607/28
• CPC Class Codes: A61B 5/35 by template matching
• CPC Class Codes: A61B 5/7217 of noise originating from a therapeutic or surgical apparatus, e.g. from a pacemaker
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: A61N 1/371 Capture, i.e. successful stimulation
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems

Abstract

Methods and devices for classifying a cardiac response to pacing involve establishing a retriggerable cardiac response classification window. A first cardiac response classification window is established subsequent to delivery of a pacing pulse. A cardiac signal following the pacing stimulation is sensed in the first classification window. A second cardiac response classification may be triggered if a trigger characteristic is detected in the first classification window. The cardiac signal is sensed in the second classification window if the second classification window is established. The cardiac response to the pacing stimulation is determined based on characteristics of the cardiac signal. The cardiac response may be determined to be one of a captured response, a non-captured response; a non-captured response added to an intrinsic beat, and a fusion/pseudofusion beat, for example.

Claims

1. A method of classifying a cardiac response to a pacing stimulation, comprising:

delivering the pacing stimulation to a heart and sensing a cardiac signal following delivery of the pacing stimulation;

sensing for a first cardiac signal peak within a first capture detection region;

in response to detecting the first cardiac signal peak within the first capture detection region, triggering a second capture detection region and sensing for a second cardiac peak within the second capture detection region;

classifying the cardiac response to the pacing stimulation as a captured response in response to detecting the first cardiac signal peak within the first capture detection region and detecting the second cardiac signal peak within the second capture detection region; and

delivering pacing therapy based on classification of the cardiac response to the pacing stimulation.

2. The method of claim 1, wherein the first cardiac signal peak has a polarity opposite to the polarity of the second cardiac signal peak.

3. The method of claim 1, further comprising determining if the cardiac signal exceeds a threshold associated with non-capture during a first interval following delivery of the pacing stimulation.

4. The method of claim 1, further comprising:

timing a first interval following delivery of the pacing stimulation; and

in response to detecting the first cardiac signal peak within the first capture detection region, timing a second interval following the first interval, wherein the first capture detection region occurs during the first interval and the second capture detection region occurs during the second interval.

5. The method of claim 1, wherein one or both of the first capture detection region and the second capture detection region has one or more adaptable boundaries.

6. The method of claim 1, wherein one or both of the first capture detection region and the second capture detection region has finite dimensions of time and amplitude.

7. The method of claim 1, further comprising triggering one or more additional detection regions and sensing for one or more additional cardiac signal features in the one or more additional detection regions.

8. The method of claim 1, wherein delivering the pacing stimulation comprises delivering a unipolar pacing stimulation.

9. The method of claim 1, wherein delivering the pacing stimulation comprises delivering a bipolar pacing stimulation.

10. The method of claim 1, wherein delivering the pacing stimulation to the heart comprises delivering the pacing stimulation to a ventricle.

11. The method of claim 1, wherein:

delivering the pacing stimulation comprises delivering the pacing stimulation using an electrode combination; and

sensing the cardiac signal following the pacing stimulation comprises sensing the cardiac signal using the electrode combination.

12. The method of claim 1, wherein:

delivering the pacing stimulation to the heart comprises delivering the pacing stimulation using a first electrode combination; and

sensing the cardiac signal following the pacing stimulation comprises sensing the cardiac signal using a second electrode combination that is different from the first electrode combination.

13. The method of claim 1, wherein sensing the cardiac signal following the pacing stimulation comprises sensing the cardiac signal using an electrode that reduces a pacing artifact signal relative to an evoked response signal.

14. The method of claim 1, wherein the first capture detection region and the second capture detection region are non-overlapping.

15. The method of claim 1, wherein the first capture detection region and the second capture detection region are separated by a time interval.

16. The method of claim 1, further comprising delivering a back up pacing stimulation if the cardiac response is classified as non-captured.

17. The method of claim 1, further comprising classifying the cardiac response as an intrinsic beat responsive to detection of the first cardiac signal peak within an intrinsic detection region.

18. The method of claim 17, wherein the intrinsic detection region has finite dimensions of time and amplitude.

19. The method of claim 17, wherein the intrinsic detection region is non-overlapping with the first and second capture detection regions.

20. The method of claim 1, further comprising classifying the cardiac response as fusion responsive to detection of the first cardiac signal peak within the first capture detection region and non-detection of the second cardiac signal peak within the second capture detection region.

21. The method of claim 1, further comprising classifying the cardiac response as fusion responsive to the cardiac signal exceeding a non-capture threshold and non-detection of the first cardiac signal peak within the first capture detection region.

22. The method of claim 1, further comprising classifying the cardiac response as fusion responsive to the cardiac signal exceeding a non-capture threshold and non-detection of the first cardiac signal peak within the first capture detection region and non-detection of a cardiac signal peak within an intrinsic detection region.

23. The method of claim 1, further comprising defining one or more detection regions respectively associated with one or more cardiac responses other than capture.

24. The method of claim 1, further comprising defining one or more detection regions respectively associated with one or more cardiac responses in addition to capture.

25. The method of claim 23, wherein the detection regions have finite dimensions of time and amplitude.

26. The method of claim 1, further comprising initializing one or both of the capture detection regions based on a plurality of cardiac signals sensed prior to delivering the stimulation pulse.

27. The method of claim 1, further comprising adapting at least one of the capture detection regions based on a location of a cardiac signal peak.

28. A cardiac rhythm management device, comprising:

pacing delivery circuitry configured to deliver a pacing stimulation to a heart;

sensing circuitry configured to a sense a cardiac signal following delivery of the pacing stimulation;

control circuitry, coupled to the sensing system, the control system configured to determine if a first cardiac signal peak of the cardiac signal falls within a first capture detection region, and, in response to the cardiac signal peak falling within the first capture detection region, to trigger a second capture detection region and sensing for a second cardiac peak of the cardiac signal within the second capture detection region, the control circuitry further configured to classify the cardiac response to the pacing stimulation as a captured response in response to detection of the first cardiac signal peak within the first capture detection region and detection of the second cardiac signal peak within the second capture detection region and to control pacing therapy based on classification of the cardiac response.

29. The device of claim 28, wherein the second cardiac signal peak has opposite polarity to the polarity of the first cardiac signal peak.

30. The device of claim 28, wherein the pulse delivery circuitry is configured to deliver the pacing stimulation to a ventricle.

31. The device of claim 28, wherein the pulse delivery circuitry is configured to deliver the pacing stimulation to an atrium.

32. The device of claim 28, wherein the sensing circuitry is configured to sense the cardiac signal using a ring electrode and a defibrillation electrode.

33. The device of claim 28, wherein the sensing circuitry is configured to sense the cardiac signal using a right ventricular coil electrode and a can electrode.

34. The device of claim 28, wherein the sensing circuitry is configured to sense the cardiac signal using a right ventricular coil electrode and a can electrode tied to an superior vena cava coil electrode.

35. The device of claim 28, wherein the control circuitry is configured to determine if the cardiac signal exceeds a threshold associated with non-capture.

36. The device of claim 28, wherein the first capture detection region has one or more adaptable boundaries.

37. The device of claim 28, wherein the second capture detection region has one or more adaptable boundaries.

38. The device of claim 28, wherein the control circuitry is further configured to trigger one or more additional detection regions and sense for one or more additional cardiac signal features in the one or more additional detection regions.

39. The device of claim 28, further comprising a switching circuit configured to selectively couple cardiac electrodes to the pacing delivery circuitry and the sensing circuitry.

40. The device of claim 28, wherein:

the pacing delivery circuitry is configured to deliver the pacing stimulation using an electrode combination; and

the sensing circuitry is configured to sense the cardiac signal following the pacing stimulation using the same electrode combination.

41. The device of claim 28, wherein:

the pacing delivery circuitry is configured to deliver the pacing stimulation using a first electrode combination; and

the sensing circuitry is configured to sense the cardiac signal following the pacing stimulation using a second electrode combination that is different from the first electrode combination.

42. The device of claim 28, wherein the first capture detection region and the second capture detection region are non-overlapping.

43. The device of claim 28, wherein the first capture detection region and the second capture detection region are separated by a time interval.

44. The device of claim 28, wherein the control circuitry is configured to determine if the cardiac signal exceeds a threshold associated with non-capture and to control delivery of a back up pacing stimulation if the cardiac signal does not exceed the threshold.

45. The device of claim 28, wherein the control circuitry is configured to classify the cardiac response as an intrinsic beat responsive to detection of the first cardiac signal peak within an intrinsic detection region.

46. The device of claim 45, wherein the intrinsic detection region has finite dimensions of time and amplitude.

47. The device of claim 45, wherein the intrinsic detection region is non-overlapping with the first and second capture detection regions.

48. The device of claim 28, wherein the control circuitry is configured to classify the cardiac response as fusion responsive to detection of the first cardiac signal peak within the first capture detection region and non-detection of the second cardiac signal peak within the second capture detection region.

49. The device of claim 28, wherein the control circuitry is configured to classify the cardiac response as fusion responsive to the cardiac signal exceeding a non-capture threshold and non-detection of the first cardiac signal peak within the first capture detection region.

50. The device of claim 28, wherein the control circuitry is configured to classify the cardiac response as fusion responsive to the cardiac signal exceeding a non-capture threshold and non-detection of the first cardiac signal peak within the first capture detection region and non-detection of a cardiac signal peak within an intrinsic detection region.

51. The device of claim 28, wherein the control circuitry is configured to use one or more detection regions respectively associated with one or more cardiac responses other than capture.

52. The device of claim 28, wherein the control circuitry is configured to use one or more detection regions respectively associated with one or more cardiac responses in addition to capture.

53. The device of claim 28, wherein the detection regions have finite dimensions of time and amplitude.

54. The device of claim 28, wherein the control circuitry is configured to initialize one or both of the capture detection regions based on a plurality of cardiac signals sensed prior to delivery of the stimulation pulse.

55. The device of claim 28, further comprising adapting one or both of the capture detection regions based on a location of a cardiac signal peak associated with the captured response.

56. The device of claim 28, wherein the pulse delivery circuitry is configured to deliver the pacing stimulation via a left ventricular distal electrode and a right ventricular coil electrode.

57. A medical system, comprising:

means for delivering a pacing stimulation to a heart;

means for sensing a cardiac signal after delivering the pacing stimulation;

means for sensing for a first cardiac signal peak within a first capture detection window;

means, responsive to detection of the first cardiac signal peak within the first capture detection region, for triggering a second capture detection region and sensing for a second cardiac signal peak within the second capture detection region;

means for classifying the cardiac response to the pacing stimulation as a captured response responsive to detection of the first cardiac signal peak in the first capture detection region and detection of the second cardiac signal peak within the second capture detection region; and

means for delivering pacing therapy based on classifying the cardiac response.

58. The medical system of claim 57, wherein the second cardiac signal peak has a polarity opposite to a polarity of the first cardiac signal peak.