METHOD AND APPARATUS FOR DETECTING ARRHYTHMIAS IN A SUBCUTANEOUS MEDICAL DEVICE

• US 20070232945A1
• Filed: 11/08/2006
• Published: 10/04/2007
• Est. Priority Date: 03/29/2006
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Kleckner, Karen J., Stadler, Robert W.
• Granted Patent: US 7,941,214 B2
• Time in Patent Office: Days
• US Class Current: 600/509
• CPC Class Codes: A61B 5/361 Detecting fibrillation
• CPC Class Codes: A61B 5/363 Detecting tachycardia or bradycardia
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61N 1/3621 for treating or preventing abnormally high heart rate
• CPC Class Codes: A61N 1/3956 Implantable devices for applying electric shocks to the heart, e.g. for cardioversion

Abstract

A method and apparatus for detecting a cardiac event in a medical device that includes sensing cardiac signals from a plurality of electrodes, charging an energy storage device in response to the sensed cardiac signals, determining whether the charging of the energy storage device is completed, and determining whether the cardiac event is confirmed in response to an asynchronous look back.

Claims

1. A method of detecting a cardiac event in a medical device, comprising:

sensing cardiac signals from a plurality of electrodes;

charging an energy storage device in response to the sensed cardiac signals;

determining whether the charging of the energy storage device is completed; and

determining whether the cardiac event is confirmed in response to an asynchronous look back.

2. The method of claim 1, wherein the plurality of electrodes are positioned non-transvenously.

3. The method of claim 1, wherein determining whether the cardiac event is confirmed in response to an asynchronous look back comprises determining whether a morphology of a signal associated with cardiac signals sensed during a look back sensing window is indicative of the cardiac event.

4. The method of claim 3, wherein the charging of the energy storage device is determined to be completed at a charging end time, and the look back sensing window extends from a window start time to a window end time, the window end time corresponding to the charging end time.

5. The method of claim 3, wherein the look back sensing window is between approximately 0.5 and 10 seconds.

6. The method of claim 3, further comprising determining, in response to the charging of the energy storage device being completed, whether the cardiac event is confirmed in response to morphologies of cardiac signals sensed during sensing windows other than the look back sensing window.

7. The method of claim 6, wherein the charging of the energy storage device is determined to be completed at a charging end time, and the look back sensing window extends from a window start time to a window end time, the window end time corresponding to the charging end time.

8. A method of detecting a cardiac event in a medical device, comprising:

sensing cardiac signals from a plurality of electrodes, the plurality of electrodes forming a first sensing vector and a second sensing vector;

charging an energy storage device in response to the sensed cardiac signals;

determining whether the charging of the energy storage device is completed; and

determining, in response to the charging of the energy storage device being completed, whether the cardiac event is confirmed in response to an asynchronous look back associated with cardiac signals sensed along the first sensing vector and the second sensing vector.

9. The method of claim 8, wherein the plurality of electrodes are positioned non-transvenously.

10. The method of claim 8, wherein determining whether the cardiac event is confirmed in response to an asynchronous look back comprises determining whether a morphology of a signal associated with cardiac signals sensed along the first sensing vector and the second sensing vector during a look back sensing window is indicative of the cardiac event.

11. The method of claim 10, wherein the cardiac event is not confirmed in response to the morphology of the signal sensed along both the first sensing vector and the second sensing vector during the look back sensing window not being indicative of the cardiac event.

12. The method of claim 10, wherein the charging of the energy storage device is determined to be completed at a charging end time, and the look back sensing window extends from a window start time to a window end time, the window end time corresponding to the charging end time.

13. The method of claim 10, wherein the look back sensing window is between approximately 0.5 and 10 seconds.

14. The method of claim 10, further comprising determining, in response to the charging of the energy storage device being completed, whether the cardiac event is confirmed in response to morphologies of cardiac signals sensed during sensing windows other than the look back sensing window.

15. The method of claim 14, wherein the charging of the energy storage device is determined to be completed at a charging end time, and the look back sensing window extends from a window start time to a window end time, the window end time corresponding to the charging end time.

16. A medical device for detecting a cardiac event and delivering a corresponding therapy, the device comprising:

a plurality of electrodes sensing cardiac signals along a first sensing vector and a second sensing vector;

an energy storage device; and

a control unit determining, in response to charging of the energy storage device being completed, whether sensing of the cardiac event is confirmed in response to an asynchronous look back associated with cardiac signals sensed along the first sensing vector and the second sensing vector.

17. The device of claim 16, wherein the plurality of electrodes are positioned non-transvenously.

18. The device of claim 16, wherein the control unit determines whether a morphology of a signal associated with cardiac signals sensed along the first sensing vector and the second sensing vector during a look back sensing window is indicative of the cardiac event.

19. The device of claim 18, wherein the control unit determines the cardiac event is not confirmed in response to the morphology of the signal sensed along both the first sensing vector and the second sensing vector during the look back sensing window not being indicative of the cardiac event.

20. The device of claim 18, wherein the control unit determines the charging of the energy storage device is completed at a charging end time, and the look back sensing window extends from a window start time to a window end time, the window end time corresponding to the charging end time.

21. The device of claim 16, wherein the look back sensing window is between approximately 0.5 and 10 seconds.

22. The device of claim 18, wherein the control unit determines, in response to the charging of the energy storage device being completed, whether the cardiac event is confirmed in response to morphologies of cardiac signals sensed during sensing windows other than the look back sensing window.

23. The device of claim 22, wherein the control unit determines the charging of the energy storage device is completed at a charging end time, and the look back sensing window extends from a window start time to a window end time, the window end time corresponding to the charging end time.

24. A medical device for detecting a cardiac event and delivering a corresponding therapy, the device comprising:

means for sensing cardiac signals from a plurality of electrodes;

means for charging of an energy storage device in response to the sensed cardiac signals;

means for determining whether the charging of the energy storage device is completed; and

means for determining whether the cardiac event is confirmed in response to an asynchronous look back.

25. The device of claim 24, wherein the plurality of electrodes are positioned non-transvenously.

26. The device of claim 24, wherein the means for determining whether the cardiac event is confirmed in response to an asynchronous look back comprises means for determining whether a morphology of a signal associated with cardiac signals sensed during a look back sensing window is indicative of the cardiac event.

27. The device of claim 26, wherein the means for determining whether the charging of the energy storage device is completed determines the charging of the energy storage device is completed at a charging end time, and wherein the look back sensing window extends from a window start time to a window end time, the window end time corresponding to the charging end time.

28. The device of claim 26 wherein the look back sensing window is between approximately 0.5 and 10 seconds.

29. The device of claim 26, further comprising means for determining, in response to the charging of the energy storage device being completed, whether the cardiac event is confirmed in response to morphologies of cardiac signals sensed during sensing windows other than the look back sensing window.

30. The device of claim 29, wherein the means for determining whether the charging of the energy storage device is completed determines the charging of the energy storage device is completed at a charging end time, and wherein the look back sensing window extends from a window start time to a window end time, the window end time corresponding to the charging end time.