RADIOFREQUENCY CATHETER ABLATION OF AN ATRIOFASCICULAR PATHWAY DURINGATRIAL-FIBRILLATION - A CASE-REPORT

Introduction: A male patient with an atriofascicular pathway underwent catheter ablation of the atriofascicular pathway during atrial fibril lation. Methods and Results: The patient had preexcited atrial fibrill ation both clinically and repeatedly during electrophysiologic study. A preexcited tachycardia with a 1:1 AV relationship and regular RR int ervals was also induced. Catheter ablation of the atriofascicular path way could only be performed during persistent atrial fibrillation, bas ed on mapping of the pathway's insertion into the right bundle branch. Following successful ablation and cardioversion to sinus rhythm, a re gular QRS tachycardia (atrioventricular [AV] nodal reentry) having the same rate, atrial activation sequence, and His-atrial time as the reg ular preexcited tachycardia noted preablation was initiated. An AV nod al slow pathway modification eliminated this tachycardia. Neither atri al fibrillation nor AV nodal reentry has recurred on follow-up. Conclu sion: This is the first report of atriofascicular mapping and ablation performed exclusively during atrial fibrillation and illustrates the utility of mapping the pathway's ventricular insertion. Other unusual features (''bystander'' pathway activation during AV nodal reentry, po ssible role of the pathway in genesis of atrial fibrillation) are disc ussed.