Endocardial catheter fulguration of ventricular tachycardia consists of sending a defibrillating shock to the tip of an endocavitary catheter lying near the site of origin of the tachycardia. The shock may modify the arrhythmogenic substrate and prevent relapses. We have used this method in 9 cases of post-infarction chronic ventricular tachycardia resistant to drug therapy, and the patients were be followed up for more than 2 years. The results were sometimes life-saving, even in cases with badly damaged myocardium. The electric shock did not significantly alter the myocardium but modified the arrythmogenic substrate enough to prevent long-term relapses. When insufficiently effective, endocardial catheter fulguration can be repeated without problems. Used alone or combined with antiarrhythmic drugs, it opens prospects of new radical therapeutic approaches.