Serum enzymes after cardiac surgery under profound hypothermia with circulatory arrest and limited cardiopulmonary bypass

Abstract Electrocardiographic and enzyme studies were made on 15 infants undergoing cardiac surgery with profound hypothermia, circulatory arrest, and limited cardiopulmonary bypass. The following observations were made preoperatively and on the first, second, and third postoperative days: 13-lead electrocardiograms, serum SGOT, LDH, LDH isoenzymes, CPK, and AP. At least one further electrocardiogram was recorded later in the hospital stay. Serum levels of AP fell after operation, but levels of the other enzymes, including all LDH isoenzymes, rose. There was no correlation between enzyme changes and the age or weight of the patient, duration of cardiopulmonary bypass, temperature at arrest, the level of hemolysis, or with postoperative complications, but the correlation with arrest time approached significant levels. The pattern of LDH isoenzyme production suggested that many tissues were involved in enzyme release.