Creatine kinase and its isoenzyme MB in patients after open heart surgery.

Total serum creatine kinase (CK) and its isoenzyme MB (CKMB) were measured before and 4, 24, 48 and 72 hours after termination of cardiopulmonary bypass in patients undergoing (I) atriotomy, (II) ventriculotomy and (III) coronary artery bypass surgery. All patients were free of postoperative complications and myocardial infarction as defined by clinical course, 12 lead ECG and 2D echocardiography. Peak elevation of CK occurred at 24th hour and CKMB at 4th hour and then gradually declined. There was no relation between the peak level of rise of CK or CKMB with cross clamp time or bypass time. The 96th percentile values of absolute CKMB level at 4, 24, 48 and 72 hours may suggest perioperative myocardial infarction with specificity of 95%. In addition, the rising value of CKMB beyond 24 hours after the termination of bypass may also suggest occurrence of myocardial infarction.