Creatine Phosphokinase Activity in Myocardial Infarction, Heart Failure, and Following Various Diagnostic and Therapeutic Procedures

The creatine phosphokinase(CPK) test based on the method of Okinaka et aI. (1) was compared with the glutamic oxalacetic transaminase (GOT) test of Reitman and Frankel (2) in patients with myocardial infarction, cardiac failure, and following variousdiagnostic and therapeutic procedures. The CPK method used was somewhat lessdiscriminatory than the GOT method in detecting myocardial infarction. The CPK test possessedgreater specificity, since it was not elevated in congestive cardiac failure, while the COT test was elevated in 25 % of the patients with heart failure. Therefore, the CPK test offered a real advantagewhen evaluating suspectedinfarction in the presence of cardiac failure. CPK activity may be elevated when the GOT test is normal, indicating the advantage of performing more than one enzyme procedure in suspectedmyocardial infarction. Both GOT and CPK were elevated in many patients following surgical operation and cardiac catheterization. No CPK elevations were encountered after electro-convulsive therapy, and CPI ( was only occasionally elevated following coronary arteriography. A NUMBER OF ENZYME TESTS have been proposed as aids in the evalua-tion of suspected myocardial infarction. Of these various tests, the one showing greatest promise has been the creatine phosphokinase (CPK) test. This enzyme is concerned with transfer of a high-energy phosphate from adenosine triphosphate to creatine, forming creatine phosphate and adeiiosine diphosphate. The test was used originally as a diagnostic aid in disease of striated muscle, but CPK activity was found also to be elevated in myocardial infarction. A major advantage claimed for the CPK assay was its greater specificity. Since CPK is limited in distribution to muscle and brain, elevated levels are said not to be encountered in some conditions which may be confused clini