The principal cardiac problems resulting from hypothermia have been spontaneous ventricular fibrillation, reduced coronary blood How, difficult return to activity after reduction to extremely low temperatures, and resuscitation after manipulation or separation from the circulation.
These problems are probably related to structural biochemical changes, conduction mechanism disturbances, and depression of activity of enzyme systems.
There are certain clues which indicate that the changes, if elucidated and controlled, might be quite simple. Clearly, the innocuous life of the mammalian hibernating animals is one. Experimentally, the untouched heart can go through prolonged, and even profoundly, low levels of hypothermia. Furthermore, there is now a large number of humans who have undergone successful cardiac and cerebrovascular surgery during periods of moderate hypothermia.
This study attempts to examine the biochemical structural changes associated with induced moderate total-body hypothermia. During the past several years the partition of electrolytes in blood following induced hypothermia has been
MOULDER PV, EICHELBERGER L, ROMA M, RAMS JJ, THURSTON C, PINC R. Biochemistry of Blood, Heart, and Skeletal Muscle Under Induced, Controlled Hypothermia. AMA Arch Surg. 1959;78(1):37-44. doi:10.1001/archsurg.1959.04320010041007