Functional and Metabolic Effects of Anoxic Cardiac Arrest

Abstract

Myocardial changes were studied in 12 dogs and 5 patients to determine whether anoxic, normothermic cardiac arrest, a simple, effective adjunct in open-heart surgery, is detrimental to cardiac function. After 30 minutes of aortic occlusion the dogs showed uniform depression of left ventricular function with profound metabolic acidosis and elevation of lactate of the coronary sinus blood. Five patients who had 21 to 45 minutes of anoxic cardioplegia also showed marked respiratory acidosis, elevation of the lactate/pyruvate ratio, and a progressive rise in lactate of the coronary sinus blood. The effects of anoxia on the human heart are comparable to those observed in the dog. We believe that anoxic cardioplegia of 45 minutes is tolerated by patients but that coronary perfusion should be employed after that length of time.