Radiofrequency ablation of atrioventricular node reentrant tachycardia: experience in 302 patients.

Radiofrequency catheter ablation was performed in 302 consecutive patients with drug refractory atrioventricular (AV) node reentrant tachycardia. Fast pathway ablation was attempted in 167 patients and was successful in 161 patients (96.4%). At a mean follow-up of 24 +/- 12 months, there were 21 tachycardia recurrences (12.5%). A second fast pathway ablation was attempted in 17 patients and was successful in all but 1 patient. Permanent complete AV block occurred in 12 patients (7.2%). Among the latter, late AV block was noted in 5 patients. Final success without pacemaker implantation was accomplished in 151 patients (90.4%). Slow pathway was attempted in 135 patients and was successful in 130 patients (96.3%). Three patients in whom slow pathway ablation failed underwent successful fast pathway ablation during the same session. At a mean follow-up of 14 +/- 11 months, there were 16 tachycardia recurrences (11.8%). A second slow pathway ablation was attempted in 16 patients and was successful in all but 1 patient. Permanent complete AV block occurred in 3 patients (2.2%). An additional patient developed 2 : 1 AV block during exercise, 3 months after ablation. Final success without pacemaker implantation was achieved in 129 patients (95.5%). Fast and slow pathway ablation had similar success and recurrence rates, procedure and fluoroscopy times, and number of radiofrequency pulses. However, the incidence of permanent complete AV block was higher following fast pathway ablation (p = 0.049). Although equally effective, slow pathway ablation is safer than fast pathway ablation, therefore, should be the first choice approach for treatment of AV node reentrant tachycardia.