Hypothermia as a valuable adjunct to intracardiac surgery has had two limiting factors which have interfered with its widespread acceptance. The relative frequency of ventricular fibrillation which may be irreversible and the short interval of safe blood-flow stasis have been the chief disadvantages observed in attempts to perform intracardiac surgery under hypothermia. The ventricular chambers are not accessible in the cold state, since ventriculotomy causes a very high incidence of fibrillation.
The cause of fibrillation is being vigorously studied in many clinics. Swan and his co-workers8 have investigated the metabolic and electrolyte changes occurring at lowered temperature. Lange, Weiner, and Gold5 found electrocardiographic changes in hypothermia suggestive of cardiac hypoxia. Penrod,6 on the other hand, believed that oxygen utilization of the heart was normal at 20C, since he found no change in coronary arteriovenous oxygen differences from those in the normothermic animal. Coronary flow was not measured
EDWARDS WS, SIMMONS E, LOMBARDO CR, BENNETT A, BING RJ. Coronary Blood Flow in HypothermiaIncidence of Ventricular Fibrillation with Decreased and Increased Coronary Flow. AMA Arch Surg. 1955;71(6):853-858. doi:10.1001/archsurg.1955.01270180059007