The long-term follow-up study (41 +/- 23 months) of 47 patients undergoing direct current ablation because of drug-resistant supraventricular arrhythmias is reported. Significant early complications occurred in four patients and included hypotension, pericarditis, nonsustained polymorphic ventricular tachycardia and one sudden death. In 42 patients (86%), complete atrioventricular (AV) block was initially achieved. During the follow-up period, AV conduction resumed in 2 of these 42 patients. Of the seven patients in whom ablation was unsuccessful, two developed late complete AV block and three had symptomatic improvement. An improved activity level was reported among 83% of the patients with successful ablation. Health care utilization manifest as the number of hospital admissions per year before and after ablation decreased significantly after ablation (2.4 +/- 2.0 versus 0.3 +/- 0.5, p less than 0.001). Echocardiographic evaluation in five patients with a depressed left ventricular ejection fraction (27 +/- 7%) before ablation showed a significant increase (45 +/- 14%, p less than 0.05) after an average follow-up period of 31 months. New onset of congestive heart failure occurred after ablation in four patients, of whom two had no structural heart disease. The total mortality rate, including the one patient with sudden death, was 17% and was significantly higher among patients with underlying structural heart disease. Transcatheter direct current ablation is an effective treatment in patients with drug-resistant supraventricular tachycardia, providing a beneficial long-term outcome including an improved quality of life and a decrease in health care utilization.(ABSTRACT TRUNCATED AT 250 WORDS)