Myocardial Hypothermia in Elective Cardiac Arrest

¹ From the Department of Surgical Research, Division of Surgery, St. Luke's Hospital, Cleveland, Ohio

Elective cardiac arrest produced by intracoronary injection of potassium citrate or acetylcholine was studied in normothermic dogs and in dogs whose hearts were cooled to about 20°C by infusion of cold blood into the coronary circulation. Potassium arrest produced a high incidence of ventricular fibrillation and poor recovery. Cardiac arrest could not be maintained with acetylcholine with or without cardiac hypothermia and ventricular fibrillation occurred in four of five dogs. Infusion of cold blood (100–200 cc) into the coronary arteries following potassium arrest gave the lowest incidence of ventricular fibrillation and the best acute recoveries, as judged by the time of pump support after aortic release, postarrest arterial and venous pressures, and the electrocardiogram. Coronary perfusion with cold blood alone, coronary perfusion with cold blood prior to potassium arrest, or potassium arrest followed by coronary perfusion with warm blood (100–200 cc) showed a high incidence of ventricular fibrillation and/or postarrest recoveries.