Catheter ablation of accessory atrioventricular pathways

pp 541-547

Abstract

Accessory atrioventricular pathways are relatively common substrate for paroxysmal supraventricular tachycardias. Chronic antiarrhythmic drug therapy has been the mainstay of treatment, but curative modalities represent attractive alternatives. Recently, percutaneous catheter ablation of accesory pathways using radiofrequency energy as power source has emerged as a safe and effective procedure. We report on 79 consecutive patients (mean age 35: t 16 years) in whom we attempt- ed catheter ablation of 85 pathways. All of them had documented symptomatic tachyarrhythmias (reciprocating tachycardias in 63, atrial fibrillation in 3, and both arrhythmias in 13). Symptoms had been present for 10 :t 9 years. Patients had undergone 1.7:t 1.2 anti- arrhythmic drug trials. An abreviated electrophysiologic study was performed at the beginning of the session. A large-tip (4 mm), steerable catheter was used for map- ping and current delivery. The energy source allowed for on-line monitoring of system impedance. Sixty pathways (70.5 0/0) had manifest antegrade conduction; 25 (29.5 %) were concealed. Location of the pathways was as follow: 22 (26 %) posteroseptal, 7 (8 %) antero- septal, 2 (2 %) intermediate septal, 49 (58 %) left free wall, and 5 (6 %) right free wall. After 92 ablation sessions (1.16 per patient), complete interruption of accessory pathway conduction was achieved in 73 patients (92 %) and 79 pathways (93 %). In 7 patients, '> one session was needed to obtain the definite cure There were no significant differencies in the success rate for patients with single versus multiple pathways or for the different accessory pathway locations. No patient died as a consequence of the procedure. Major complications occurred in two patients. One patient with a intermediate septal pathway developed complete heart block during energy delivery and subsequently required a permanent pacemaker. Another patient developed cardiac tamponade after a successful left- sided ablation and required thoracotomy for repair of a left ventricular perforation. Patients were discharged from hospital 2.5:t 2.3 days after the procedure. We conclude that percutaneous radiofrequency catheter ablation of accessory atrioventricular pathways is a safe and effective procedure. It should be considered as treatment of first choice for symptomatic patients with tachyarrhythmias associated with accessory pathways.