The AV junction ablation was useful to treat patients with drug-refractory supraventricular arrhythmias. The purpose of this study was to determine short and long-term success and complications of the atrioventricular nodal catheter ablation and to compare direct current and radiofrequency energy. Forty patients underwent AV nodal ablation with direct current energy (Group I) and forty patients with radiofrequency (Group II). They were followed up for a mean of 76 +/- 49 and 28 +/- 20 months, respectively. Persistent complete AV block was successfully induced during the first ablation session in 45% of 40 patients who underwent DC energy, while in 50% it was modulated. All patients in the radiofrequency group had complete AV block. The rate of recurrence of AV conduction was 7.5% and 2.5% respectively. Immediate complications did not occur after either procedure. One patient died suddenly in each group during follow-up. AV nodal ablation with radiofrequency energy appears to be as efficacious and safe as direct current energy.