Pacemakers do not always tell the truth: diagnosis of ventricular tachycardia for supraventricular tachycardia on pacemaker telemetry.

Pacemaker telemetry reflects algorithm-dependent interpretations about the cardiac rhythm. For these data to be useful, it is necessary to recognize the limitations of each algorithm and its interactions with pacing and sensing parameters. We report on a case in which pacemaker Holter recording showed several episodes of nonsustained supraventricular tachycardia which were erroneously classified as ventricular tachycardia.