Patent ID: 7130683

Claim:
A system for implementing a preferential atrial-based pacing regimen, the system comprising: means for implementing an atrial-based pacing mode wherein a complete cardiac cycle is permitted to transpire without ventricular activity, a venticular back-up pace is provided in a dual chamber mode in a cardiac cycle immediately subsequent to a cardiac cycle devoid of ventricular activity, and the system is returned to the atrial-base pacing mode in a cardiac cycle immediately subsequent to the cardiac cycle including the ventricular back-up pace; means for detecting relatively reliable AV conduction according to a reliability criteria threshold; means for automatically switching to a DDD/R mode in the event that the relatively reliable AV conduction is not detected; means for altering the DDD/R mode so that an intrinsic ventricular depolarization may emerge; means for resuming the atrial-based pacing mode in the event that the intrinsic ventricular depolarization emerges; and means for delivering a ventricular pace stimulus at the expiration of a predetermined AV conduction interval in the event that said intrinsic ventricular depolarization does not emerge.