This report describes a modified defibrillation technique used successfully in a patient with an implanted epicardial cardioverter defibrillator who developed refractory ventricular fibrillation. During operative testing at the time of generator replacement, two episodes of intractable ventricular fibrillation were terminated by using a combined internal (epicardial)-external (transthoracic) defibrillation system that delivered a 360-J shock between the anterior epicardial patch and a large posterior skin electrode.