Reduction of the arrhythmia was obtained in 1 to 5 days, spontaneously (2 cases) of after oral amiodarone (500 to 2000 mg/m2/24 hr) (5 cases) or intravenous flecainide or propafenone in the two most critically ill patients. With the exception of 1 patient who was successfully treated with propranolol for 1 year, amiodarone was prescribed in all cases for 7 to 36 months after reversion to sinus rhythm: 5 children have been taken off treatment and seem to be completely cured 4 to 9 years after withdrawal; the other 3 patients have not had recurrences but have only been treated for 6 to 15 months. One of them has neurological sequellae from a cerebral embolism originating from an atrial thrombus. These results show that incessant ventricular tachycardia in infancy is a serious condition but amenable to medical treatment with high dose amiodarone or, when poorly tolerated, intravenous Class 1c antiarrhythmics for reduction of the arrhythmia, and amiodarone at adequate doses for 2 years to prevent recurrence. With the exception of the rare arrhythmogenic right ventricular dysplasia, the long term prognosis would seem to be excellent and, in general, there would seem to be little need for surgery.