Inappropriate pacing due to autoperpetuation of the ventricular rate stabilization algorithm: a manifestation of T wave oversensing by ICDs.

Preventive pacing algorithms designed to eliminate the pause that follows a premature ventricular depolarization have been incorporated in current implantable defibrillators. We report a patient in whom intermittent T wave oversensing frequently invoked the ventricular rate stabilization algorithm and resulted in periods of inappropriate VVI pacing. The problem was solved by decreasing the maximum sensitivity from 0.3 mV to 0.45 mV. Implant testing had revealed adequate sensing of ventricular fibrillation with a maximum sensitivity of 1.2 mV.