Comparison of alternating current with direct current electroshock across the closed chest

I T IS BECOMING increasingly recognized that ventricular fibrillation is an important cause of sudden death. The treatment of this arrhythmia is by electrical countershock delivered to the heart either directly or indirectly through the intact chest wall. From the onset of ventricular fibrillation only a few minutes are available for restoring an integrated cardiac mechanism. Until recently the successful use of countershock has been largely limited to the operating room where this brief time could be prolonged by the prompt institution of direct cardiac massage. The demonstration by Kouwenhoven and co-workers1 that in the arrested heart pressure on the lower sternum maintains blood flow to vital organs has greatly extended the time available for effective use of electrical defibrillation. Recently it has been shown2-4 that electrical countershock across the closed chest will abolish cardiac arrhythmias other than ventricular fibrillation. It is therefore pertinent to determine whether alternating current, widely accepted for inducing countershock, is indeed the best available method. The present study compared the action on the heart of alternating current and three types of direct current both during ventricular fibrillation and during normal sinus rhythm.