DIAGNOSIS OF ACUTE MYOCARDIAL-INFARCTION IN A COMMUNITY-HOSPITAL - SIGNIFICANCE OF CPK-MB DETERMINATION

Twice-daily CPK-MB determinations were performed but not made available to the physicians of 179 consecutive patients with precordial pain admitted to a community hospital to evaluate the diagnostic importance of this isoenzyme. Physician decision was based upon history and once-daily ECG and total enzymes (creatine phospholtinase, serum glutamate oxaloacetic transaminge and lactate dehydrogenase]. Following hospital discharge, each patient''s clinical record was reviewed to determine the physician diagnostic decision. The patients were subdivided into 3 groups. The 1st group consisted of 46 patients with diagnostic QRS changes and elevated total enzymes. All 46 had physician diagnosis of acute myocardial infarction and CPK-MB was present in 44 (96%). The 2nd group included 55 patients with nondiagnostic QRS but elevated total enzymes. Physician diagnosis was acute myocardial infarction in 28 (51%) but 16 (57%) of these had no CPK-MB. The 3rd group contained 50 patients with nondiagnostic QRS and normal enzyme levels. Six (12%) had physician diagnosis of acute myocardial infarction but none had CPK-MB. Thus, absence of CPK-MB failed to confirm physician diagnosis of acute myocardial infarction when based upon history and total enzymes in the absence of QRS changes in 22 of 34 (65%) patients.