Patent ID: 7515959

Claim:
A method for operating a cardiac rhythm management device, comprising: sensing atrial depolarizations through an implanted atrial electrode; administering a sequential cardiac resynchronization therapy (CRT) pacing therapy in a sequential CRT pacing mode to a left and right ventricle of a heart of a patient via implanted ventricular electrodes in a sequential bi-ventricular fashion; detecting an atrial arrhythmia in response to the sensed atrial depolarizations according to a first threshold for determination of atrial arrhythmia; switching from the sequential CRT pacing mode to a simultaneous CRT pacing mode in response to detecting the atrial arrhythmia according to the first threshold; administering a simultaneous CRT pacing therapy in the simultaneous CRT pacing mode to the left and right ventricle in a simultaneous bi-ventricular fashion; and analyzing the sensed atrial depolarizations during the simultaneous CRT pacing therapy to confirm the presence of the detected atrial arrhythmia according to a second threshold for determination of the atrial arrhythmia, the second threshold higher than the first threshold.