Abstract: An implantable medical device includes cardiac pacing functions. In order to reduce ventricular pacing, various modes are employed that tolerate missed ventricular beats, provide backup pacing and maintain overall AV synchrony. Upon the occurrence of a PVC, A-A timing is modified so that resultant V-V intervals are appropriate and ventricular pacing is avoided.

Abstract: An atrial based pacing protocol promotes intrinsic conduction. An entire cardiac cycle is monitored for ventricular activity and permitted to lapse with ventricular activity. Ventricular pacing is available in a cardiac cycle immediately subsequent to such a skipped beat. When monitoring for intrinsic ventricular events, an event is expected within a given window. If no such event is detected, the cardiac cycle in truncated, leading to a shorter cycle that is devoid of ventricular activity. The subsequent cycle has a high likelihood of a ventricular sensed event and a greater than normal AV interval is provided prior to pacing.

Abstract: An atrial based pacing protocol promotes intrinsic conduction. An entire cardiac cycle is monitored for ventricular activity and permitted to lapse with ventricular activity. Ventricular pacing is available in a cardiac cycle immediately subsequent to such a skipped beat. When monitoring for intrinsic ventricular events, an event is expected within a given window. If no such event is detected, the cardiac cycle in truncated, leading to a shorter cycle that is devoid of ventricular activity. The subsequent cycle has a high likelihood of a ventricular sensed event and a greater than normal AV interval is provided prior to pacing.

Abstract: The present invention is directed to the problem of preventing episodes of “AV Desynchronization Arrhythmia” (AVDA), a dual-chamber pacing behavior that is initiated by a PVC or other ventricular event that is not closely preceded by an atrial depolarization event. If the initiating PVC creates retrograde conduction resulting in an atrial refractory-sensed event, and should the succeeding AP fail to capture due to pacing within the atrial refractory period (ARP) a repetitive AVDA sequence (APineffectual-VP-ARrefractory) can persist for an extended period of time and symptoms of pacemaker syndrome can occur. After AVDA detection, the following may occur: delivered atrial pacing (AP) energy may be (dynamically) increased, a atrial pacing (AP) delay interval may be implemented, a mode-switch may be executed, a patient notification process may begin, a histogram may be recorded or processed, and/or a combination thereof may be used in response the detected AVDA sequence.

Abstract: The present invention is directed to the problem of preventing episodes of “AV Desynchronization Arrhythmia” (AVDA), a dual-chamber pacing behavior that is initiated by a PVC or other ventricular event that is not closely preceded by an atrial depolarization event. If the initiating PVC creates retrograde conduction resulting in an atrial refractory-sensed event, and should the succeeding AP fail to capture due to pacing within the atrial refractory period (ARP) a repetitive AVDA sequence (APineffectual-VP-ARrefractory) can persist for an extended period of time and symptoms of pacemaker syndrome can occur. After AVDA detection, the following may occur: delivered atrial pacing (AP) energy may be (dynamically) increased, a atrial pacing (AP) delay interval may be implemented, a mode-switch may be executed, a patient notification process may begin, a histogram may be recorded or processed, and/or a combination thereof may be used in response the detected AVDA sequence.