Feasibility and Effectiveness of Low-Energy Catheter Defibrillation in Man

The effectiveness of low energy intraventricular catheter defibrillation was evaluated in 11 patients undergoing coronary artery surgery, in whom ventricular fibrillation occurred after anoxic arrest of 21-42 min. A distal electrode catheter was introduced through an atriotomy into the right ventricular apex. In eight patients the proximal electrode was a saline-soaked sponge placed on the superior vena cava, while in three this electrode formed an integral part of the superior vena cava cannula used in cardiopulmonary bypass. Intraventricular catheter defibrillation was accomplished in nine patients using 5-15 w-sec, considerably less energy than required for paddle defibrillation. There were no apparent short or long-term ill effects. Unsuccessful defibrillation in the two remaining patients was ascribed to difficulties in electrode placement. The effectiveness of low energy intraventricular catheter defibrillation in man, in addition to raising basic electrophysiologic questions, provides background for the development of the transvenous automatic defibrillator for protection of selected high-risk patients.