RESUMO
Atrioventricular nodal reentry tachycardia (AVNRT) is one of the most mechanisms of paroxysmal supraventricular tachycardia. In these patients tachycardia is maintained due to anterograde conduction through a slow pathway and retrograde conduction to the atrium via a fast pathway. We present here our experience in ablation of the slow pathway. Since January 1993, 30 consecutive patients with AVNRT underwent attempted catheter ablation of the slow pathway. Mean age was 37ñ3.7 years. All patients had symptomatic tachycardia and six had history of syncope. Electrophysiological studies revealed AVNRT in all patients, in addition, 2 patients had a left accesory pathway. Slow pathway ablation was performed with Mansfield 7 F catheter, guided by both fluoroscopic positioning and endocardial signals. A mean of 13 burst were applied. In the 30 patients conduction though the slow pathway was interrupted and thus tachycardia was no longer inductible. Retrograde conduction post ablation was evaluated in 17 of the 30 patients, significant changes were observed in three of them. One patient developed second degree AV block and a permanent pacemaker was implanted. Another patient had recurrence of tachycardia three months post ablation. After a second attempt she is arrhythmia free. Patients have been followed for a mean of 15.7ñ2.5 months and are asymptomatic in the absence of antiarrhythmic therapy