Patent ID: 8024042

Claim:
A method for controlling intervals timed by an implantable cardiac pacing device configured for delivering minimum ventricular pacing, the method comprising: sensing intrinsic atrial events in an atrial chamber; sensing intrinsic ventricular events in a ventricular chamber; setting an atrial-only pacing mode in response to sensing the intrinsic ventricular events in the ventricular chamber; setting a first post-ventricular atrial refractory period following each of a plurality of ventricular events sensed in the ventricular chamber; detecting a plurality of atrial events each being sensed during first post-ventricular atrial refractory periods; setting a second post-ventricular atrial refractory period following a single intrinsic ventricular event in response to detecting the plurality of atrial events, the second post-ventricular atrial refractory period being shorter than the first post-ventricular atrial refractory period so that a next intrinsic atrial event is sensed outside the second post-ventricular atrial refractory period and establishes a pattern of an atrial non-refractory event sensed in the atrial chamber (AS) followed by a ventricular event sensed in the ventricular chamber (VS); and maintaining the atrial-only pacing mode in response to establishing the AS-VS pattern.