Dual chamber pacing system and method with continual adjustment of the AV escape interval so as to maintain optimized ventricular pacing for treating cardiomyopathy

• US 5,716,383 A
• Filed: 06/24/1996
• Issued: 02/10/1998
• Est. Priority Date: 02/28/1996
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Hess, Michael F., Kieval, Robert S.
• Primary Examiner(s): Jastrzab, Jeffrey R.
• Application Number:
  US08/669,188
• Time in Patent Office: 596 Days
• Field of Search: 607/9, 607/17, 607/25, 607/27, 607/28
• US Class Current: 607/9
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/3682 with a variable atrioventricular delay

Abstract

A dual chamber pacemaker is provided having capability for adjusting the AV escape interval so as to optimize the timing of delivered ventricular pace pulses for therapy of patients with cardiomyopathy. The pacemaker system continually monitors to determine when a delivered pace pulse results in a fusion beat, and periodically adjusts the AV escape interval in accordance with the percentage or rate of incidence of such fusion beats. In one specific embodiment, the pacing system determines the percentage of delivered ventricular pace pulses which are followed by fusion beats over a predetermined number of intervals, and decrements AV escape interval when such percentage is not below a predetermined minimum. The pacing system also periodically increments AV escape interval when the rate of fusion beats is acceptable, thereby providing a closed loop system for maintaining the AV interval at an optimally long value consistent with maximizing full capture by delivered ventricular pace pulses. In another embodiment, the V--V escape interval of a non-tracking mode pacemaker is controlled to optimize pre-excitation of the ventricle.

Claims

1. A method of pacing therapy using a pacemaker in a non-tracking mode comprising:

detecting atrial events,

delivering ventricular pace pulses to a patient without a timed relationship to detected atrial events.

changing the V--V escape interval of delivered ventricular pace pulses, and determining, when one or more said changed interval delivered ventricular pace pulses fail to result in full capture of the ventricle, and shortening said V--V escape interval in response to a determination of such a failure, and further comprising detecting the patient'"'"'s rate of spontaneous atrial beats, detecting when the atrial rate is above a predetermined atrial high rate limit, and initiating delivery of said ventricular pace pulses upon detecting an atrial rate above said high rate limit.

2. The method of pacing therapy as described in claim 1, comprising initially delivering said ventricular pace pulses at a predetermined ventricular high rate limit upon detecting an atrial rate above said atrial high rate limit.

3. The method of pacing therapy as described in claim 2, further comprising limiting the duration of pacing at said ventricular high rate limit.

4. The method of pacing therapy as described in claim 1 wherein said changing comprises periodically increasing said V--V escape interval.

5. The method of pacing therapy as described in claim 1, wherein said determining step comprises determining when a delivered pace pulse results in a fusion beat.

6. A dual chamber pacemaker, having ventricular pace means for generating and delivering ventricular pace pulses to said patient'"'"'s right ventricle, and sync control means for controlling said ventricular pace pulses to said patient'"'"'s right ventricle, and sync control means for controlling said ventricular pace means to generate and deliver a ventricular pace pulse at a controlled VV escape interval, said sync control means having VV_esc means for setting said VV escape interval said VV_esc means comprising:

Means for detecting when one or more of said ventricular pace pulses fails to result in full capture of the ventricle and adjustment means for shortening said VV escape interval in response to a determination of such failure, said pacemaker further comprising means for sensing natural atrial depolarizations so as to determine a spontaneous atrial rate and mode means responsive to a determination of a high atrial rate by said means for sensing and for initiating asynchronous ventricular pacing responsive to such a determination of high atrial rate.