tients die in the wards and the delay in instituting treat¬ ment, in general, mitigate against success. In the 13 instances of totally unexpected cardiac arrest in the operating room, 7 patients (including one with ventricu¬ lar fibrillation) have been successfully resuscitated. In the six cases of ventricular fibrillation occurring during di¬ rect attacks on the heart, all hearts were defibrillated but only three of these patients survived.