Ischemic myocardial injury following aorto-coronary bypass surgery.

To assess the incidence of acute myocardial injury following aorto-coronary bypass surgery 151 patients (136 men and 15 women) were evaluated by studying serial preoperative and postoperative ECGs and SGOT, LDH and CPK levels. The mean age of men was 49.1 and of women, 53.1 years. Following surgery 15 patients (group I, 9.9 percent) developed new myocardial infarction as judged by Q wave criteria, 33 patients (group II, 22.5 percent) developed significant ST-T changes, and 103 patients (group III, 68 percent) had no significant ECG change. Mean postoperative SGOT values were: group I,126.2; group II, 100.6; and group III, 72.8. Only the difference in SGOT values between group I and III was significant (P less than 0.01). There was no correlation between type and site of surgery and the incidence of myocardial infarction. There were five deaths (3.3 percent). The combination of death and diagnosed myocardial infarction amounted to 12.6 percent of patients for this widely used elective procedure.