Serum CK-MB kinetics in acute myocardial infarction and after coronary bypass operations.

Serum creatine kinase (CK) isoenzyme MB and total CK activity concentrations in 11 patients with acute myocardial infarction (AMI) were compared with the corresponding enzyme activities in 25 patients after coronary bypass surgery, not complicated clinically by AMI. Peak CK-MB occurred 2 +/- 0 (mean +/- SEM) hours after the end of surgery (mean duration of operation 6 hours), but 17 +/- 1 hours from the onset of symptoms in AMI. The plasma half"life for CK-MB was 11 +/- 1 hours under both conditions. Peak total CK was found after about 20 hours in both series of patients. Total CK half-life was 17 +/- 2 hours in AMI, but 30 +/- 3 hours following surgery. CK kinetics were thus different in these two situations, indicating different mechanisms for the elevations of serum CK-MB activity. In conclusion, the time course for the transient CK-MB elevation following bypass surgery should be considered in the diagnosis of peri operative infarction.