Radiofrequency catheter ablation was performed in 100 men and 81 women, mean age 78 +/- 5 years, referred for ablation of atrial flutter, supraventricular tachycardia, and ventricular tachycardia, and for ablation of the atrioventricular junction with permanent pacemaker implantation in patients with atrial fibrillation and a rapid ventricular rate not controlled by drug therapy. A hematoma in 1 of 182 ablation procedures (<1%) was the only complication. Radiofrequency catheter ablation was successful in treating 63 of 70 patients (90%) with atrial flutter, in treating 60 of 66 patients (91%) with supraventricular tachycardia, in treating 2 of 2 patients (100%) with ventricular tachycardia, and in ablating the atrioventricular junction in 43 of 44 patients (98%) with atrial fibrillation and a rapid ventricular rate not controlled by drug therapy.