| 摘要 |
A dual chamber pacemaker system and method are provided for placing the pacemaker in an asynchronous mode when retrograde conduction is present, having the capability of detecting the onset of retrograde conduction and also monitoring on a cycle-by-cycle basis to determine the end of retrograde conduction. The detection of end of retrograde conduction is accomplished by two operative algorithms, i.e., a first algorithm which is executed at the time of any atrial sense and a second algorithm which is executed at the time of each ventricular event. Following an atrial sense, the pacemaker checks to see whether the just concluded VA interval conforms to predetermined RC interval criteria, and if not, immediately switches the pacemaker out of the RC mode and into a synchronous tracking mode. Following each ventricular event while the pacemaker is in the RC mode, the pacemaker monitors a predetermined class of special events and determines end of RC upon detection of a pattern of such special events. In a specific embodiment, if there are n (e.g.,3) consecutive cycles wherein the VA interval differs from the VA interval of the previous cycle by more than a predetermined amount, this is determined to establish a pattern indicative of end of RC; upon detection of this pattern, the pacemaker immediately switches to a synchronous tracking mode of pacing.
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