Endocavitary fulgurations were practised in 26 cases of high risk ventricular tachycardia (VT) for which antiarrhythmics including amiodarone and class I antiarrhythmic agents given alone or in combination proved ineffectiveness. Permanent VT was present in nine patients at the time of the fulguration session: three were moribund, and two were unconscious. Included in the series were 10 cases of arrhythmogenic right ventricular dysplasia, nine patients had chronic VT several months after myocardial infarction, four had a non obstructive cardiomyopathy, two were idiopathic and one came after repair of the right ventricular outflow tract. Fulguration succeeded in preventing VT in the 22 patients who survived the initial period of treatment in association with therapeutic antiarrhythmics, in eight cases. Three of the four early deaths were probably related to imperfections in the technique. Two late deaths were due to spontaneous evolution of the disease. The follow-up period ranges from a minimum of 15 to a maximum of 34 months, with an average follow-up of nearly two years. The success rate of fulguration alone or for patients receiving prophylactic antiarrhythmic drugs is 90%. Ten patients required two sessions or more before VT was brought under control.