Creatine kinase-MB activity after implantation of a cardiac pacemaker

Identification of creatine kinase (CK) isoenzyme CK-MB has made an excellent improvement of the diagnosis of myocardial infarction. 1 Cardiac muscle contains relatively large amounts of CK-MB. CK-MB is also present in skeletal muscle. Injury to skeletal muscle may therefore result in elevation of “non-cardiac” CK-MB and cause difficulties in the diagnosis of myocardial infarction. 2,3 Elevation of CK-MB may also be expected in direct cardiac muscle injury, but previous studies reflecting this relation have shown only a slight increase in CK-MB isoenzyme activity. 4 This study evaluates total CK and isoenzyme CK-MB activity in patients undergoing cardiac pacemaker implantation. In this procedure there is injury to cardiac and skeletal muscle.