RADIOFREQUENCY ABLATION OF AV-NODAL REENT RY TACHYCARDIA - EXPERIENCEWITH SELECTIVE FAST PATHWAY ABLATION

AV-nodal reentrant tachycardia (AVNRT) is a common cause of recurrent supraventricular tachycardia. Currently, catheter ablation of either s low or fast pathway are nonpharmacologic options for the treatment of patients with AVNRT. Radiofrequency (RF) catheter ablation of the fast pathway was attempted in 35 patients (aged 46.7 +/- 15 years; 12 m, 2 3 f) with recurrent AVNRT RF energy (25-50 watt, 30-90 s) was delivere d to the anterior right atrial septum. The catheter was placed posteri or to the largest His bundle deflection. AV conduction was monitored d uring continuous pacing of the high right atrium while the RF current was applied. RF-ablation was acutely successful using a mean of 6.5 +/ - 6.2 impulses in 31 patients. Late spontaneous block of the slow path way occurred in one patient (pat. 17) with an unsuccessful initial att empt of fast pathway ablation. PQ and AH interval increased significan tly after the ablation procedure (PQ: from 149 +/- 27 to 208 +/- 34 ms , AH: from 76 +/- 22 to 131 +/- 38 ms; p value: < 0.0001). Acute inter ruption of retrograde VA conduction was the result in 23 patients. Six patients (17 %) had a recurrence of AVNRT during a follow-up period o f 11.9 +/- 7.5 months. Five of 6 patients underwent a second successfu l procedure. Complete AV block occurred in 3 of the first 10 consecuti ve patients and in none of the subsequent 25 patients (overall inciden ce: 8.6 %). Thus, RF ablation of the fast retrograde pathway is an eff ective method for the curative treatment of AVNRT. The relatively high initial incidence of complete AV block could be substantially reduced after a learning curve. However, the overall risk of AV block remains a severe complication of fast pathway ablation.