CONCERTINA-LIKE PHENOMENON IN VENTRICULAR PREEXCITATION DUE TO SPONTANEOUS ATRIOVENTRICULAR NODAL WENCKEBACH PERIODICITY

Electrophysiologic study and radiofrequency ablation therapy were perf ormed in a 28-year-old male patient with the Wolff-Parkinson-White syn drome and electrocardiographic manifestation of concertina phenomenon His bundle recordings showed a sinus cycle length of 720=ms with a cyc lic variation of QRS morphologies of every 3 beats and an antidromic a trial echo following the last fully preexcited QRS complex. After succ essful radiofrequency ablation of a left posterior accessory pathway, spontaneous 3:2 atrioventricular nodal `Wenckebach periodicity was not ed and the mechanism of the concertina phenomenon was unraveled.