Atrioventricular nodal reentrant tachycardia diagnosed by pacemaker electrograms.

Electrograms stored by pacemakers or implantable defibrillators enable the diagnosis of numerous atrial or ventricular arrhythmia episodes. We present the case of a patient implanted with a DDD pacemaker for sinus node dysfunction who experienced episodes of tachycardia. Atrioventricular nodal reentrant tachycardia was diagnosed by real-time analysis of electrograms during and at the onset of the tachycardia episodes. Electrophysiological study confirmed the diagnosis and led to radical treatment of the tachycardia by radiofrequency ablation of the slow pathway.