THE EFFECTIVENESS of direct-current (DC) countershock in the treatment of arrhythmias that are refractory to drug therapy has been established,1but the safety of the procedure is still questioned. Electric burns, myocardial injury, and asystole are feared complications. In experimental studies, Lown and associates1have noted electrocardiographic changes compatible with myocardial infarction in one third of the dogs that received DC countershock. The purpose of this communication is to report the use of DC countershock at least 140 times in a patient, with no resulting damage to the myocardium, as demonstrated at autopsy examination. Report of a Case A 62-year-old man was admitted to Cleveland Clinic Hospital on Oct 14, 1962, for investigation and treatment of hypertension. He had known of his hypertension for two years and had been receiving reserpine and a diuretic, which were only moderately effective. For two years he had had occasional episodes