System and method of identifying fusion for dual-chamber automatic capture stimulation device

• US 6,904,321 B1
• Filed: 07/29/2002
• Issued: 06/07/2005
• Est. Priority Date: 08/02/2000
• Status: Expired due to Term

• Current Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Original Assignee: Pacesetter Incorporated (Abbott Laboratories)
• Inventors: Florio, Joseph J., Bornzin, Gene A., Sloman, Laurence S.
• Primary Examiner(s): Getzow, Scott M.
• Application Number:
  US10/208,169
• Time in Patent Office: 1,044 Days
• Field of Search: 607 2- 30
• US Class Current: 607/27
• CPC Class Codes: A61N 1/3712 Auto-capture, i.e. automatic adjustment of the stimulation threshold

Abstract

A multi-chamber stimulation device and associated method reliably and automatically distinguish fusion from loss of capture during ventricular stimulation. The stimulation device provides immediate and accurate fusion detection when a loss of capture is suspected in the ventricles without delivering back-up stimulation pulses. To achieve this objective, the far-field signal present in the atrial channel is examined for evidence of a far-field R-wave whenever the ventricular channel detects a loss of capture. If a far-field R-wave is present, fusion is confirmed, and a far-field R-wave is absent, loss of capture is confirmed. Additionally, the stimulation device inhibits unnecessary back-up stimulation and threshold tests when fusion occurs, and provides appropriate adjustment of stimulation parameters based on confirmed fusion detection such that fusion re-occurrence is minimized.

Claims

1. A method of detecting ventricular fusion events, the method comprising:

delivering a ventricular stimulation pulse;

monitoring a ventricular channel for an evoked response;

monitoring an atrial channel for a far-field R-wave; and

indicating a fusion event when an evoked response is not detected on the ventricular channel and the far-field R-wave is detected on the atrial channel.

2. The method according to claim 1, further comprising inhibiting delivery of a back-up stimulation pulse whenever the fusion event is indicated.

3. The method according to claim 1, further comprising indicating a loss of capture when an evoked response is not detected on the ventricular channel and a far-field R-wave is not detected on the atrial channel, and delivering a back-up stimulation pulse.

4. The method according to claim 1, further comprising automatically adjusting at least one stimulation parameter whenever the fusion event is indicated.

5. The method according to claim 4, wherein automatically adjusting at least one stimulation parameter comprises automatically adjusting at least one of an AV interval and a PV interval subsequent to an indication of the fusion event.

6. The method according to claim 4, wherein automatically adjusting at least one stimulation parameter comprises automatically adjusting a stimulation rate subsequent to an indication of the fusion event.

7. The method according to claim 1, wherein delivering comprises delivering the stimulation pulse in at least one of a right ventricular chamber or a left ventricular chamber.

8. The method according to claim 7, wherein detecting the far-field R-waves comprises analyzing an atrial intra-cardiac electrogram signal following the delivery of the ventricular stimulation pulse.

9. The method according to claim 8, further comprising:

detecting a ventricular evoked response on the ventricular channel based on a predetermined criteria; and

triggering the detection of the far-field R-wave on the atrial channel when the detected ventricular evoked response does not match the predetermined criteria.

10. The method according to claim 9, wherein indicating the fusion event comprises indicating that the far-field R-wave on the atrial channel substantially coincides in time with the detected ventricular evoked response that does not match the predetermined criteria.

11. A stimulation device for detecting a fusion event, the stimulation device comprising:

a pulse generator configured to generate a ventricular stimulation pulse;

ventricular sensing circuitry that is operative to monitor for an evoked response following delivery of the ventricular stimulation pulse;

atrial sensing circuitry that is operative to monitor for a far-field R-wave following delivery of the ventricular stimulation pulse; and

a controller connected to the atrial sensing circuitry and ventricular sensing circuitry, wherein the controller is configured to detect a fusion event when the evoked response is not detected and the far-field R-wave is detected.

12. The stimulation device according to claim 11, wherein the controller inhibits delivery of a back-up stimulation pulse if the fusion event is confirmed.

13. The stimulation device according to claim 12, wherein the controller causes the pulse generator to deliver a back-up stimulation pulse if the evoked response is not detected and the far-field R-wave is not detected.

14. The stimulation device according to claim 11, wherein the controller automatically adjusts one or more stimulation parameters if the fusion event is confirmed.

15. The stimulation device according to claim 11, wherein the controller performs capture verification in at least one of a right ventricular chamber and a left ventricular chamber.

16. The stimulation device according to claim 15, wherein the atrial sensing circuitry samples an atrial intra-cardiac electrogram signal following delivery of the ventricular stimulation pulse.

17. The stimulation device according to claim 11, wherein the ventricular sensing circuitry is operative to sample a ventricular intra-cardiac electrogram signal from the ventricular chamber in which the stimulation pulse is applied;

and

wherein the controller performs ventricular evoked response verification by determining when an evoked response is detected from a sampled ventricular intra-cardiac electrogram signal.

18. The stimulation device according to claim 17, wherein the controller confirms the occurrence of the fusion event when a far-field R-wave substantially coincides in time with an evoked response on the ventricular channel that is below a predetermined threshold.

19. A method for detecting a fusion event, the method comprising:

delivering a stimulation pulse in a ventricular chamber;

following the delivered stimulation pulse, detecting a signal on a ventricular channel that does not satisfy a predetermined criteria associated with an evoked response signal;

following the delivered stimulation pulse, detecting one of an absence or a presence of a far-field R-wave on an atrial channel;

inhibiting delivery of a back-up stimulation pulse when the far-field R-wave is present; and

delivering a back-up stimulation pulse when the far-field R-wave is absent.

20. The method according to claim 19, wherein delivering comprises delivering the stimulation pulse in at least one of a right ventricular chamber or a left ventricular chamber.

21. The method according to claim 19, wherein detecting the absence or presence of the far-field R-waves comprises analyzing an atrial intra-cardiac electrogram signal following the delivery of the ventricular stimulation pulse.

22. The method according to claim 21, further comprising:

indicating a fusion event when the far-field R-wave on the atrial channel substantially coincides in time with the detected ventricular evoked response that does not meet the predetermined criteria.