Patent ID: 8391974

Claim:
A cardiac pacemaker, comprising: sensing amplifiers for sensing atrial and ventricular depolarizations; pulse generators for delivering paces to the right and left ventricles; a controller for controlling the delivery of paces in accordance with a primary pacing mode that delivers paces to only one ventricle; wherein the controller is configured to switch the pacemaker to an atrial fibrillation pacing mode upon detection of an atrial tachyarrhythmia, wherein the atrial fibrillation pacing mode includes a biventricular pacing mode that delivers paces to both left and right ventricles in a non-atrial triggered pacing mode in which the controller adjusts a ventricular escape interval in order to regularize the rate at which ventricular beats occur by increasing the ventricular escape interval after a ventricular pace is delivered and decreasing the ventricular escape interval after a ventricular sense.