Successful Radiofrequency Catheter Ablation of Nonreentrant Supraventricular Tachycardia Due to Simultaneous Conduction Through Dual Atrioventricular Nodal Pathways

Abstract

Double ventricular response (DVR) was found to induce atrioventricular reentrant tachycardia or atrioventricular nodal reentrant tachycardia. We experienced a rare case with antegrade dual nonreentrant tachycardia (NRT) eliminated radiofrequency (RF) ablation. A 74-year-old man suffered from palpitation. Supravenrticular tachycardia, which consisted of similarity to bigeminy and RR irregularity, were recognized during 24-hour ambulatory electrocardiogram in all days. That showed two distinct PR intervals of about 0.18 and 0.46 second, suggestive of dual atrioventricular nodal pathways (DAVNP). To verify DVR using by electrophysiological study, DVR through DAVNP were observed by atrial single extrastimulus method. Establishment of DVR was followed; overlap of the fast and slow AV nodal pathway conduction curves was noted at coupling intervals between 700 and 330 msec, and ventriculoatrial conduction was absent, The differences of conduction time between fast pathway and slow pathway, was longer than ventricular effective refractory period. Disopyramide was terminated and prevented the tachycardia but appearing side effect of urinary retention. RF catheter ablation for selective slow pathway was performed during only antegade slow pathway. When RF energy was delivered, DVR were successfully eliminated and the tachycardia cured completely. Conclusion: As far as we examined the literatures, it was rare that NRT persisted in all days, and was eliminated through only antegrade slow pathway by RF ablation.