Method and system for detecting capture with cancellation of pacing artifact

• US 20070129766A1
• Filed: 01/09/2007
• Published: 06/07/2007
• Est. Priority Date: 12/31/2002
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Bocek, Joseph, Kim, Jaeho
• Granted Patent: US 7,702,393 B2
• Time in Patent Office: Days
• US Class Current: 607/28
• CPC Class Codes: A61N 1/3712 Auto-capture, i.e. automatic adjustment of the stimulation threshold

Abstract

Methods and systems for detecting capture using pacing artifact cancellation are described. One or more pacing artifact templates are provided and a cardiac signal is sensed in a cardiac verification window. Each of the pacing artifact templates may characterize the pacing artifact associated with a particular pacing energy level, for example. A particular pacing artifact template is canceled from the cardiac signal. Capture is determined using the pacing artifact canceled cardiac signal. Detection of fusion/pseudofusion beats may be accomplished by comparing a cardiac signal to a captured response template.

Claims

1. A method for detecting fusion/pseudofusion in a cardiac beat, comprising:

detecting a cardiac signal;

canceling a captured response template from the cardiac signal to form a captured response canceled cardiac signal; and

detecting fusion/pseudofusion using the captured response canceled cardiac signal.

2. The method of claim 1, further comprising updating the captured response template using a cardiac signal representative of a captured cardiac beat.

3. The method of claim 1, further comprising

detecting a plurality of cardiac signals representing captured cardiac beats;

combining the cardiac signals to form the captured response template; and

storing the captured response template.

4. The method of claim 1, wherein the cardiac signal is detected in a fusion/pseudofusion detection window.

5. The method of claim 4, wherein the fusion/pseudofusion detection window begins at the end of a blanking period and has a length of about 20 ms.

6. The method of claim 1, wherein detecting fusion/pseudofusion comprises discriminating a fusion/pseudofusion beat from a captured beat.

7. The method of claim 1, further comprising:

canceling a pacing artifact template from the cardiac signal; and

detecting capture using the pacing artifact canceled signal.

8. The method of claim 7, further comprising:

providing a plurality of pacing artifact templates; and

selecting the pacing artifact template from the plurality of pacing artifact templates.

9. The method of claim 8, wherein each pacing artifact template of the plurality of pacing artifact templates is respectively associated with a pace pulse amplitude or a range of pace pulse amplitudes.

10. The method of claim 7, wherein the pacing artifact template is estimated as an exponential function or a combination of exponential functions.

11. A medical device, comprising:

electrodes electrically coupled to the heart;

pulse generator circuitry coupled to the electrodes and configured to provide stimulation pulses to the heart;

sensing circuitry coupled to the electrodes and configured to sense a cardiac signal; and

a capture detection system configured to provide a captured response template, to cancel the captured response template from the sensed cardiac signal, and to detect fusion/pseudofusion using the captured response canceled cardiac signal.

12. The medical device of claim 11, wherein the capture detection system is further configured to update the captured response template using a cardiac signal representative of a captured cardiac beat.

13. The medical device of claim 11, wherein the capture detection system is further configured to discriminate a fusion/pseudofusion beat from a captured beat.

14. The medical device of claim 11, wherein the capture detection system is configured to detect capture.

15. The medical device of claim 11, wherein the capture detection system is configured to cancel a pacing artifact template from the cardiac signal and detect capture using the pacing artifact canceled signal.

16. The medical device of claim 15, wherein the capture detection system is configured to provide a plurality of pacing artifact templates and to select the pacing artifact template from the plurality of pacing artifact templates.

17. The medical device of claim 16, wherein each pacing artifact template of the plurality of pacing artifact templates is respectively associated with a range of pace pulse amplitudes.

18. A system, comprising:

a sensing system configured to sense a cardiac signal;

means for canceling a captured response template from the cardiac signal to form a captured response canceled cardiac signal; and

means for detecting fusion/pseudofusion using the captured response canceled cardiac signal.

19. The system of claim 18, further comprising means for updating the captured response template using a cardiac signal representative of a captured cardiac beat.

20. The system of claim 18, further comprising means for detecting capture.

21. The system of claim 18, further comprising means for discriminating a fusion/pseudofusion beat from a captured beat.