Method and system for atrial capture detection based on far-field R-wave sensing

• US 6,658,293 B2
• Filed: 04/27/2001
• Issued: 12/02/2003
• Est. Priority Date: 04/27/2001
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Vonk, Ben F. M.
• Primary Examiner(s): Schaetzle, Kennedy
• Application Number:
  US09/842,882
• Publication Number:
  US 20020183798A1
• Time in Patent Office: 949 Days
• Field of Search: 607/28, 607/27, 607/9, 607/62, 600/521
• US Class Current: 607/28
• CPC Class Codes: A61N 1/3712 Auto-capture, i.e. automatic adjustment of the stimulation threshold
• CPC Class Codes: A61N 1/3714 Atrial capture
• CPC Class Codes: A61N 1/3716 with reduction of residual polarisation effects

Abstract

A method and system for atrial capture detection based on far-field R-wave (FFRW) sensing is provided. After establishing that stable FFRW sensing exists, presence of atrial capture can be detected by atrial sensing of the FFRW in a predetermined FFRW detection window following an atrial pace. Threshold values for the atrial pace can be determined by varying an atrial test variable and observing whether a FFRW occurs in the FFRW detection window. In another embodiment, threshold values for the atrial pace can be determined by applying a search pace before the regular atrial pace, varying an atrial test variable for the search pace, and monitoring the movement of the FFRW between the FFRW detection window and a predetermined search detection window located before the FFRW detection window.

Claims

1. A method for detecting atrial capture, comprising:

determining whether stable FFRW sensing is present;

measuring a FFRW detection time if stable FFRW sensing is present;

specifying a FFRW detection window around the FFRW detection time;

applying an atrial pace; and

monitoring the FFRW detection window for a FFRW in response to the atrial pace.

2. The method of claim 1, wherein determining whether stable FFRW sensing is present further comprises:

applying atrial paces at a normal heart rate; and

verifying FFRWs are detected in the atrium in response to the atrial paces.

3. The method of claim 2, further comprising:

applying a predetermined number of successive atrial paces, and

verifying the predetermined number of successive FFRWs are detected in the atrium in response to successive atrial paces.

4. The method of claim 3, wherein the predetermined number is from 5 to 20.

5. The method of claim 4, wherein the predetermined number is 10.

6. The method of claim 1, wherein the FFRW detection window is 50 msec wide and centered at an average FFRW detection time after the atrial pace.

7. The method of claim 1, further comprising:

determining a threshold value for an atrial test variable of the atrial pace by changing the value of the atrial test variable in small increments; and

determining the threshold value when the FFRW is no longer seen in the FFRW detection window.

8. The method of claim 7, wherein the atrial test variable is selected from the group consisting of amplitude and pulse width.

9. The method of claim 8, wherein the small increment for changing the amplitude is 0.1 to 0.5 V.

10. The method of claim 9, wherein the small increment for changing the amplitude is 0.1 V.

11. The method of claim 8, wherein the small increment for changing the pulse width is 0.05 msec.

12. The method of claim 1, further comprising:

determining a threshold value for an atrial test variable of the atrial pace by changing the value of the atrial test variable in small increments; and

determining the threshold value when the FFRW appears in the FFRW detection window.

13. The method of claim 12, wherein the atrial test variable is selected from the group consisting of amplitude and pulse width.

14. The method of claim 13, wherein the small increment for changing the amplitude is 0.1 to 0.5 V.

15. The method of claim 14, wherein the small increment for changing the amplitude is 0.1 V.

16. The method of claim 13, wherein the small increment for changing the pulse width is 0.05 msec.

17. The method of claim 1, further comprising:

specifying a search detection window at a time difference before the FFRW detection time;

applying a search pace at the time difference before the atrial pace;

determining a threshold value for an atrial test variable of the search pace by changing the value of the atrial test variable in small increments; and

determining the threshold value when the FFRW moves between the FFRW detection window and the search detection window.

18. The method of claim 17, wherein the atrial test variable is selected from the group consisting of amplitude and pulse width.

19. The method of claim 18, wherein the small increment for changing the amplitude is 0.1 to 0.5 V.

20. The method of claim 19, wherein the small increment for changing the amplitude is 0.1 V.

21. The method of claim 18, wherein the small increment for changing the pulse width is 0.05 msec.

22. The method of claim 17, wherein the search detection window is 50 msec wide and centered at an average FFRW detection time after the search pace.

23. An implantable medical system, comprising:

means for determining whether stable FFRW sensing is present;

means for measuring a FFRW detection time if stable FFRW sensing is present;

means for specifying a FFRW detection window around the FFRW detection time;

means for applying an atrial pace; and

means for monitoring the FFRW detection window for a FFRW in response to the atrial pace.

24. The system of claim 23, wherein the means for determining whether stable FFRW sensing is present further comprise:

means for applying atrial paces at a normal heart rate; and

means for verifying FFRWs are detected in the atrium in response to the atrial paces.

25. The system of claim 24, further comprising

means for applying a predetermined number of successive atrial paces, and

means for verifying the predetermined number of successive FFRWs are detected in the atrium in response to successive atrial paces.

26. The system of claim 25, wherein the predetermined number is from 5 to 20.

27. The system of claim 26, wherein the predetermined number is 10.

28. The system of claim 23, wherein the FFRW detection window is 50 msec wide and centered at an average FFRW detection time after the atrial pace.

29. The system of claim 23, further comprising:

means for determining a threshold value for an atrial test variable of the atrial pace by changing the value of the atrial test variable in small increments; and

means for determining the threshold value when the FFRW is no longer seen in the FFRW detection window.

30. The system of claim 29, wherein the atrial test variable is selected from the group consisting of amplitude and pulse width.

31. The system of claim 30, wherein the small increment for changing the amplitude is 0.1 to 0.5 V.

32. The system of claim 31, wherein the small increment for changing the amplitude is 0.1 V.

33. The system of claim 30, wherein the small increment for changing the pulse width is 0.05 msec.

34. The system of claim 23, further comprising:

means for determining a threshold value for an atrial test variable of the atrial pace by changing the value of the atrial test variable in small increments; and

means for determining the threshold value when the FFRW appears in the FFRW detection window.

35. The system of claim 34, wherein the atrial test variable is selected from the group consisting of amplitude and pulse width.

36. The system of claim 35, wherein the small increment for changing the amplitude is 0.1 to 0.5 V.

37. The system of claim 36, wherein the small increment for changing the amplitude is 0.1 V.

38. The system of claim 35, wherein the small increment for changing the pulse width is 0.05 msec.

39. The system of claim 23, further comprising:

means for specifying a search detection window at a time difference before the FFRW detection time;

means for applying a search pace at the time difference before the atrial pace;

means for determining a threshold value for an atrial test variable of the search pace by changing the value of the atrial test variable in small increments; and

means for determining the threshold value when the FFRW moves between the FFRW detection window and the search detection window.

40. The system of claim 39, wherein the atrial test variable is selected from the group consisting of amplitude and pulse width.

41. The system of claim 40, wherein the small increment for changing the amplitude is 0.1 to 0.5 V.

42. The system of claim 41, wherein the small increment for changing the amplitude is 0.1 V.

43. The system of claim 39, wherein the small increment for changing the pulse width is 0.05 msec.

44. The system of claim 39, wherein the search detection window is 50 msec wide and centered at an average FFRW detection time after the search pace.

45. A computer usable medium storing computer readable program code having a program for detecting atrial capture, comprising:

computer readable program code for determining whether stable FFRW sensing is present;

computer readable program code for measuring a FFRW detection time if stable FFRW sensing is present;

computer readable program code for specifying a FFRW detection window around the FFRW detection time;

computer readable program code for applying an atrial pace; and

computer readable program code for monitoring the FFRW detection window for a FFRW in response to the atrial pace.

46. The program of claim 45, wherein the computer readable program code for determining whether stable FFRW sensing is present further comprises:

computer readable program code for applying atrial paces at a normal heart rate; and

computer readable program code for verifying FFRWs are detected in the atrium in response to the atrial paces.

47. The program of claim 46, further comprising

computer readable program code for applying a predetermined number of successive atrial paces, and

computer readable program code for verifying the predetermined number of successive FFRWs are detected in the atrium in response to successive atrial paces.

48. The program of claim 47, wherein the predetermined number is from 5 to 20.

49. The program of claim 48, wherein the predetermined number is 10.

50. The program of claim 45, wherein the FFRW detection window is 50 msec wide and centered at an average FFRW detection time after the atrial pace.

51. The program of claim 45, further comprising:

computer readable program code for determining a threshold value for an atrial test variable of the atrial pace by changing the value of the atrial test variable in small increments; and

computer readable program code for determining the threshold value when the FFRW is no longer seen in the FFRW detection window.

52. The program of claim 51, wherein the atrial test variable is selected from the group consisting of amplitude and pulse width.

53. The program of claim 52 wherein the small increment for changing the amplitude is 0.1 to 0.5 V.

54. The program of claim 53, wherein the small increment for changing the amplitude is 0.1 V.

55. The program of claim 52, wherein the small increment for changing the pulse width is 0.05 msec.

56. The program of claim 45, further comprising:

computer readable program code for determining a threshold value for an atrial test variable of the atrial pace by changing the value of the atrial test variable in small increments; and

computer readable program code for determining the threshold value when the FFRW appears in the FFRW detection window.

57. The program of claim 56, wherein the atrial test variable is selected from the group consisting of amplitude and pulse width.

58. The program of claim 57, wherein the small increment for changing the amplitude is 0.1 to 0.5 V.

59. The program of claim 58, wherein the small increment for changing the amplitude is 0.1 V.

60. The program of claim 57, wherein the small increment for changing the pulse width is 0.05 msec.

61. The program of claim 45, further comprising:

computer readable program code for specifying a search detection window at a time difference before the FFRW detection time;

computer readable program code for applying a search pace at the time difference before the atrial pace;

computer readable program code for determining a threshold value for an atrial test variable of the search pace by changing the value of the atrial test variable in small increments; and

computer readable program code for determining the threshold value when the FFRW moves between the FFRW detection window and the search detection window.

62. The program of claim 61, wherein the atrial test variable is selected from the group consisting of amplitude and pulse width.

63. The program of claim 62, wherein the small increment for changing the amplitude is 0.1 to 0.5 V.

64. The program of claim 63, wherein the small increment for changing the amplitude is 0.1 V.

65. The program of claim 64, wherein the small increment for changing the pulse width is 0.05 msec.

66. The program of claim 61, wherein the search detection window is 50 msec wide and centered at an average FFRW detection time after the search pace.