Catheter ablation of ventricular tachycardias was performed in a total of 80 patients whose tachycardias were considered as drug refractory and who were not considered to be candidates for antitachycardic surgery or implantation of an automatic cardioverter defibrillator. After careful endocardial catheter mapping including pacing interventions, either direct-current (DC) (n = 61) or radiofrequency current (RF) (n = 13) or both (n = 6) were applied of the "site of origin" of ventricular tachycardia or the "zone of slow conduction". 42 of 51 patients with coronary heart disease were discharged; ventricular tachycardia recurred in 8 cases, and 2 patients died suddenly. In the remaining 32 patients, there were no recurrences of ventricular tachycardia during a mean follow-up period of 12 month. Three patients died perioperatively. In 21 of 29 patients without coronary artery disease, no recurrences of ventricular tachycardia were observed (mean duration of follow-up 17 months) whereas 8 cases had a recurrence of ventricular tachycardia.