Description
Creatine phosphokinase (CPK) is widely distributed and is primarily involved with ATP regeneration in conjunction with the contractile and transport systems. The enzyme is dimeric and exists in three isoenzyme forms: MM (muscle), MB (heart) and BB (brain). The hybrid isoenzyme (MB) has the highest concentration in the heart muscle. Therefore, determination of the serum CPK level of this isoenzyme has been used as a sensitive index for the diagnosis of myocardial infarction. Elevated levels of the BB isoenzyme of CPK have been reported in the serum of patients immediately following cardiac surgery. The CPK-BB levels in serum returned to normal by the fourth post-operative day. This may be a more sensitive diagnostic tool than the serum levels of CPK-MB isoenzyme in cardiac patients