Myocardial and non-myocardial release of myoglobin and creatine-kinase MB following cardiac operations with hypothermic potassium cardioplegia

Serum time-activity curves for myoglobin, creatine-kinase (CK) and its isoenzyme MB were determined during and after coronary bypass surgery and aortic valve replacement. Hypothermic potassium cardioplegia was the method employed to initiate cardiac arrest. Cardiac myoglobin and CK-MB release rates were maximal 0.5 to 1.0 h post aortic cross-clamp release (PACR) with maximal concentrations at 1 and 4 h PACR respectively. The cardiac release ceased within 5 h PACR but was followed by a noncardiac release with maximal concentrations from 10 to 35 h PACR. The cardiac myoglobin release was significantly lower in the coronary bypass group, whereas no significant intergroup difference was observed for CK-MB. The cumulative CK-MB release corresponded roughly to about 5 g of myocardium.