Abstract
The levels of creatine kinase, hydroxybutyric dehydrogenase, and aspartate transaminase have been serially measured in the serum of patients undergoing surgery. Serum enzyme levels often rose to a range commonly found after myocardial infarction but fell to normal within 5-10 days. Raised serum enzyme levels have no diagnostic significance in a case of postoperative chest pain until after the fifth postoperative day, but may be significant thereafter.