Noise canceling cardiac electrodes

• US 20040230243A1
• Filed: 12/17/2003
• Published: 11/18/2004
• Est. Priority Date: 04/11/2003
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Haefner, Paul, Brockway, Marina, Kamath, Apurv, Shiroff, Jason Alan, Wagner, Darrell Orvin
• Granted Patent: US 7,499,750 B2
• Time in Patent Office: Days
• US Class Current: 607/27
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• CPC Class Codes: A61N 1/0568 with drug delivery
• CPC Class Codes: A61N 1/0587 Epicardial electrode systems; Endocardial electrodes piercing the pericardium
• CPC Class Codes: A61N 1/36542 controlled by body motion, e.g. acceleration
• CPC Class Codes: A61N 1/36585 controlled by two or more physical parameters
• CPC Class Codes: A61N 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion
• CPC Class Codes: A61N 1/39622 Pacing therapy

Abstract

Implementing a subcutaneous medical electrode system involves positioning a number of electrode subsystems in relation to a heart so that noise cancellation provides an improved signal to noise ratio of the cardiac signal and/or to provide one electrode arrangement preferential for cardiac signals and another arrangement preferential for noise signals. One of the electrode subsystems so positioned may include one or more can electrodes located on a housing enclosing a medical device. The medical device may be configured to provide therapeutic, diagnostic, or monitoring functions, including, for example, cardiac arrhythmia therapy.

Claims

1. A cardiac device, comprising:

a pulse generator comprising a controller; and

a plurality of implantable electrodes coupled to the pulse generator and arranged in a spaced relationship with respect to cardiac tissue and vasculature for transthoracic cardiac sensing, the plurality of electrodes comprising;

a first combination of electrodes adapted to preferentially sense cardiac signals; and

a second combination of electrodes adapted to preferentially sense noise signals.

2. The device of claim 1, wherein the first combination of electrodes is selected by the controller to preferentially sense the cardiac signals, and the second combination of electrodes is selected by the controller to preferentially sense the noise signals.

3. The device of claim 2, wherein the controller selects combinations of the plurality of electrodes, and senses a cardiac signal component and a noise component of signals acquired by each of the controller selected electrode combinations.

4. The device of claim 2, wherein:

the controller selects the first combination of electrodes as an electrode combination that provides a cardiac signal response that exceeds a threshold; and

the controller selects the second combination of electrodes as an electrode combination that provides a noise component response.

5. The device of claim 2, wherein:

the controller selects the first combination of electrodes as an electrode combination that provides a cardiac signal response that exceeds a signal-to-noise ratio threshold; and

the controller selects the second combination of electrodes as an electrode combination that provides a cardiac signal response substantially lower than the signal-to-noise ratio threshold.

6. The device of claim 2, wherein:

the controller selects the first combination of electrodes as an electrode combination that provides a cardiac signal response that exceeds a threshold; and

the controller selects the second combination of electrodes as an electrode combination that provides a cardiac signal response substantially lower than the threshold.

7. The device of claim 1, wherein the cardiac signals sensed by the first combination of electrodes comprise a cardiac signal component and a noise component, the controller reducing the noise component of the cardiac signals using the sensed noise signals.

8. The device of claim 1, wherein the first combination of electrodes is arranged to preferentially sense the cardiac signals and the second combination of electrodes is arranged to preferentially sense the noise signals.

9. The device of claim 1, wherein the first combination of electrodes is arranged in a spatially diverse relationship relative to the second combination of electrodes.

10. The device of claim 1, wherein the first combination of electrodes is arranged spatially orthogonal to the second combination of electrodes.

11. The device of claim 1, wherein:

the first combination of electrodes is arranged to provide a cardiac signal response that exceeds a signal-to-noise ratio threshold; and

the second combination of electrodes is arranged to provide a cardiac signal response substantially lower than the signal-to-noise ratio threshold.

12. The device of claim 1, wherein:

the first combination of electrodes is arranged to provide a cardiac signal response that exceeds a first signal-to-noise ratio threshold; and

the second combination of electrodes is arranged to provide a cardiac signal response lower than a second signal-to-noise ratio threshold.

13. The device of claim 1, wherein:

the first combination of electrodes is arranged to provide a cardiac signal response that exceeds a threshold; and

the second combination of electrodes is arranged to provide a cardiac signal response substantially lower than the threshold.

14. The device of claim 1, wherein:

the first combination of electrodes is arranged to provide a cardiac signal response that exceeds a first threshold; and

the second combination of electrodes is arranged to provide a cardiac signal response lower than a second threshold.

15. The device of claim 1, wherein:

the first electrode combination comprises electrodes positioned about a patient'"'"'s heart; and

the second electrode combination comprises electrodes positioned about the patient'"'"'s heart.

16. The device of claim 15, wherein the first electrode combination includes at least one electrode from the second electrode combination.

17. The device of claim 15, wherein the second electrode combination includes at least one electrode from the first electrode combination.

18. The device of claim 1, wherein a first and a second electrode of one or both of the first and second electrode combinations are positioned in an opposing relationship about a patient'"'"'s heart.

19. The device of claim 1, wherein each of the electrodes of one or both of the first and second electrode combinations is positioned relative to a particular surface of a patient'"'"'s heart.

20. The device of claim 1, wherein the first electrode combination comprises n electrodes positioned at a first location relative to a patient'"'"'s heart and at least n+1 electrodes positioned at a second location relative to the patient'"'"'s heart, where n is an integer equal to or greater than 1.

21. The device of claim 1, wherein the second electrode combination comprises n electrodes positioned at a first location relative to a patient'"'"'s heart and at least n+1 electrodes positioned at a second location relative to the patient'"'"'s heart, where n is an integer equal to or greater than 1.

22. A cardiac device, comprising:

a pulse generator comprising a controller; and

a plurality of surface electrodes coupled to the pulse generator and arranged in a spaced relationship with respect to a patient'"'"'s heart for sensing cardiac activity, the plurality of electrodes comprising;

a first combination of electrodes adapted to preferentially sense cardiac signals; and

a second combination of electrodes adapted to preferentially sense noise signals.

23. The device of claim 22, wherein the first combination of electrodes is selected by the controller to preferentially sense the cardiac signals, and the second combination of electrodes is selected by the controller to preferentially sense the noise signals.

24. The device of claim 23, wherein the controller selects combinations of the plurality of electrodes, and senses a cardiac signal component and a noise component of signals acquired by each of the controller selected electrode combinations.

25. The device of claim 23, wherein:

the controller selects the first combination of electrodes as an electrode combination that provides a cardiac signal response that exceeds a threshold; and

the controller selects the second combination of electrodes as an electrode combination that provides a noise component response.

26. The device of claim 23, wherein:

the controller selects the first combination of electrodes as an electrode combination that provides a cardiac signal response that exceeds a signal-to-noise ratio threshold; and

the controller selects the second combination of electrodes as an electrode combination that provides a cardiac signal response substantially lower than the signal-to-noise ratio threshold.

27. The device of claim 26, wherein the first electrode combination includes at least one electrode from the second electrode combination.

28. The device of claim 26, wherein the second electrode combination includes at least one electrode from the first electrode combination.

29. The device of claim 22, wherein the cardiac signals sensed by the first combination of electrodes comprise a cardiac signal component and a noise component, the controller reducing the noise component of the cardiac signals using the sensed noise signals.

30. The device of claim 22, wherein the cardiac signals sensed by the first combination of electrodes comprise a cardiac signal component and a noise component, the controller linearly combining the sensed cardiac signals with the sensed noise signals to reduce the noise component of the cardiac signals.

31. The device of claim 22, wherein the cardiac signals sensed by the first combination of electrodes comprise a cardiac signal component and a noise component, the controller selecting a therapy using the noise component.

32. The device of claim 22, wherein selecting the first and second sensing vectors comprises selecting a first combination of electrodes that is spatially separate to a second combination of electrodes, the first combination of electrodes providing the first sensing vector and the second combination of electrodes providing the second sensing vector.

33. A method of sensing cardiac activity, comprising:

providing a plurality of implantable electrodes, each of the electrodes arranged in a spaced relationship with respect to cardiac tissue and vasculature for transthoracic cardiac sensing, the electrodes selectively combinable to define a plurality of sensing vectors;

selecting a first sensing vector of the plurality of sensing vectors which is preferentially sensitive to signals associated with the cardiac activity; and

selecting a second sensing vector of the plurality of sensing vectors which is preferentially sensitive to noise signals.

34. The method of claim 33, further comprising selecting combinations of the plurality of electrodes, and sensing a cardiac signal component and a noise component of signals acquired by each of the selected electrode combinations.

35. The method of claim 33, wherein:

selecting the first sensing vector comprises selecting a combination of electrodes that provides a cardiac signal response that exceeds a threshold; and

selecting the second sensing vector comprises selecting a combination of electrodes that provides a noise component response.

36. The method of claim 33, wherein:

selecting the first sensing vector comprises selecting a combination of electrodes that provides a cardiac signal response that exceeds a signal-to-noise ratio threshold; and

selecting the second sensing vector comprises selecting a combination of electrodes that provides a cardiac signal response substantially lower than the signal-to-noise ratio threshold.

37. The method of claim 33, wherein:

selecting the first sensing vector comprises selecting a combination of electrodes that provides a cardiac signal response that exceeds a first signal-to-noise ratio threshold; and

selecting the second sensing vector comprises selecting a combination of electrodes that provides a cardiac signal response lower than a second signal-to-noise ratio threshold.

38. The method of claim 33, wherein:

selecting the first sensing vector comprises selecting a combination of electrodes that provides a cardiac signal response that exceeds a first threshold; and

selecting the second sensing vector comprises selecting a combination of electrodes that provides a cardiac signal response lower than a second threshold.

39. The method of claim 33, wherein:

selecting the first sensing vector comprises selecting a combination of electrodes that provides a cardiac signal response that exceeds a threshold; and

selecting the second sensing vector comprises selecting a combination of electrodes that provides a cardiac signal response substantially lower than the threshold.

40. The method of claim 33, wherein:

selecting the first sensing vector comprises selecting a first combination of electrodes positioned about a patient'"'"'s heart; and

selecting the second sensing vector comprises selecting a second combination of electrodes positioned about the patient'"'"'s heart.

41. The method of claim 40, wherein selecting the first electrode combination comprises selecting at least one electrode from the second electrode combination.

42. The method of claim 40, wherein selecting the second electrode combination comprises selecting at least one electrode from the first electrode combination.

43. The method of claim 40, wherein a first and a second electrode of one or both of the first and second electrode combinations are positioned in an opposing relationship about the patient'"'"'s heart.

44. The method of claim 40, wherein each of the electrodes of one or both of the first and second electrode combinations is positioned adjacent a particular surface of the patient'"'"'s heart.

45. The method of claim 33, wherein selecting the first sensing vector comprises selecting a first electrode combination comprising n electrodes positioned at a first location relative to a patient'"'"'s heart and at least n+1 electrodes positioned at a second location relative to the patient'"'"'s heart, where n is an integer equal to or greater than 1.

46. The method of claim 33, wherein selecting the second sensing vector comprises selecting a second electrode combination comprising n electrodes positioned at a first location relative to a patient'"'"'s heart and at least n+1 electrodes positioned at a second location relative to the patient'"'"'s heart, where n is an integer equal to or greater than 1.

47. The method of claim 33, wherein at least one of the electrodes selected to provide one or both of the first and second sensing vectors are provided at a housing of the pulse generator.

48. The method of claim 33, wherein at least one of the electrodes selected to provide one or both of the first and second sensing vectors define electrically shielded electrodes.

49. The method of claim 33, further comprising reducing a noise component of cardiac activity signals using the noise signals.

50. The method of claim 33, further comprising linearly combining cardiac activity signals with the noise signals to reduce a noise component of the cardiac activity signals.

51. The method of claim 33, further comprising linearly combining the first sensing vector and the second sensing vector to reduce the noise component of a cardiac signal.

52. The method of claim 33, further comprising linearly combining the first sensing vector and the second sensing vector to provide a cardiac signal.

53. A method of sensing cardiac activity, comprising:

providing a plurality of implantable electrodes, each of the electrodes arranged in a spaced relationship with respect to cardiac tissue and vasculature for transthoracic cardiac sensing, the electrodes selectively combinable to define a plurality of sensing vectors;

selecting a first sensing vector of the plurality of sensing vectors; and

selecting a second sensing vector of the plurality of sensing vectors, wherein the first sensing vector and the second sensing vector are adjacent and about parallel.

54. The method of claim 53, further comprising linearly combining the first sensing vector and the second sensing vector by scaling the first sensing vector and subtracting the scaled first sensing vector from the second sensing vector to provide a noise signal.