Radiofrequency current is highly effective in ablating accessory pathways, with low morbidity and no mortality.

Catheter ablation of 215 accessory pathways (APs) using radiofrequency current (RF) was attempted in 204 consecutive patients. Two hundred twelve of the 215 (99%) APs were successfully ablated. After a minimum of follow-up period of 1 month (mean 8.5 +/- 5.4 months), AP conduction had returned in 17 patients (8%). Recurrence of AP conduction was manifest by atrioventricular (AV) reentrant tachycardia in six patients, palpitations suggestive of AV reentrant tachycardia in five patients, ventricular preexcitation on electrocardiogram in five patients, and inducible AV reentrant tachycardia during a follow-up electrophysiological study in one asymptomatic patient. AP conduction returned as early as 12 hours and as late as 4.7 months, but was evident within 2 months of ablation in 15 of 17 (88%) patients. AP conduction recurred in 12%-14% of anteroseptal, right free-wall, and posteroseptal APs, but only 5% of left free-wall APs (P less than 0.01). Retrograde only conducting APs (concealed APs) had recurrence of AP conduction more frequently (16%) than APs that exhibited antegrade conduction (5.5%; P less than 0.01). Failure to record AP potentials from the ablation electrode, reflecting poor AP localization, was a strong predictor for recurrence of AP conduction. AP conduction returned in 19% of 48 APs when AP potentials were not recorded, compared to 5% of 164 APs where AP potentials were recorded from the ablation electrode (P less than 0.01). The time to block of AP conduction from the onset of RF current application was longer in APs with recurrence of conduction (4.9 +/- 6.1 sec vs 2.9 +/- 3.4 sec; P less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

We conclude that catheter-delivered radiofrequency current effectively produces complete atrioventricular block (94%) without requiring general anesthesia or the risk of ventricular dysfunction or cardiac perforation. The large-tip electrode allows a threefold increase in delivered power and markedly decreases the number of pulses and time required to produce atrioventricular block.