A case of creatine kinase isomer anomaly in relation to the diagnosis of acute myocardial infarction.

Creatine kinase (CK) isomers have recently been suggested to be of value in the diagnosis of acute myocardial infarction (AMI). The aim of this report was to determine whether measurement of CK isomers, especially the MM isomer and the cardio-specific marker MB isomer, is practical in the diagnosis of AMI. A 64-year-old female with consistently high values for total CK showed an electrophoretic pattern which suggested AMI. We ruled out all possible causes of increased CK, and its MB isomer, including IgGBB, beta-LP (lipoprotein) and mitochondrial complexes as well as myocarditis, muscular disorders, and myoglobinuria. Regardless of the source of the anomaly, the fact remains that CK macroanomaly cases can be an obstacle in the diagnosis of AMI. CK isomers have proven to be accurate markers in AMI and valuable in doubtful cases, such as non Q-AMI. However, in light of this particular case of CK macroanomaly, isomers are not 100% accurate (specific) in the diagnosis of AMI.