Anoxic cardiac arrest: Its effect on myocardial mitochondrial metabolism

Forty eight healthy dogs are subjects to cardiopulmonary bypass and divide into two groups according to whether the perfusion is performed in normothermia or moderate hypothermia (30 degrees C). The effects on oxidative phosphorylation and mitochondrial respiration, produced by increasing periods of myocardial anoxia from aortic cross clamping, are studied. A clear correlation is found between the disturbances of mitochondrial metabolism and the future cardiac recovery. Hypothermia shows a protective effect on the anoxic myocardium. It is concluded that the period of absolute safety in cardiac anoxia, as far as mitochondrial function is concerned, is 15 minutes in normal thermic perfusion and 90 minutes in moderately hypothermic ones.