Radioimmunoassay of serum creatine kinase B isoenzyme in the diagnosis of acute myocardial infarction. Correlation with technetium-99m stannous pyrophosphate myocardial scintigraphy

In 80 patients admitted to a coronary care unit within 24 hours of chest pain thought to be due to acute myocardial infarction, routine diagnostic tests (electrocardiograms, total serum creatine kinase) as well as ^99mtechnetium stannous pyrophosphate, TcPYP myocardial scintigraphy and serial serum radioimmunoassay determinations of the B subunit of creatine kinase (CK-B), were performed. None of these patients had clinical evidence of acute cerebral injury. A definite decision regarding the presence of acute myocardial infarction could be made in 77 patients on the basis of the results of routine diagnostic tests. The calculated sensitivity, specificity and predictive value of an elevated serum CK-B level in the recognition of acute myocardial infarction were each 100 per cent. Serial TcPYP scintigraphy was 97 per cent sensitive and 70 per cent specific, and had a predictive value of 96 per cent for the recognition of acute myocardial infarction. Both serum CK-B analysis and TcPYP myocardial scintigraphy were helpful in the recognition of infarct extension, and serial studies with both techniques suggested the presence of asymptomatic extension of infarction in several patients. The predictive value of each of these techniques for the recognition of a myocardial infarct suggests that both may be of diagnostic assistance to the physician in clinical settings in which the history, electrocardiogram or total serum creatine kinase are for some reason not interpretable. These techniques may also prove complementary in furthering the ability to assess the extent of acute myocardial damage and the course of its progression.