Patent ID: 7050852

Claim:
A method for operating a cardiac pacemaker, comprising: generating atrial sense signals with one or more atrial sensing channels; pacing an atrium in accordance with a normal pacing mode having a specified atrial escape intervals, wherein the normal pacing mode includes raising the atrial escape interval to a hysteresis value following an atrial sense, the escape interval remaining at the hysteresis value until an atrial pace is delivered; estimating an intrinsic atrial conduction time based upon one or more atrial sense signals during the normal pacing mode while hysteresis of the atrial escape interval is operative; comparing the estimated atrial conduction time with a specified limit value; switching from the normal pacing mode to an atrial pacing preference mode if the estimated atrial conduction time exceeds the specified limit value, wherein the atrial pacing preference mode includes discontinuing hysteresis with respect to the atrial escape interval.