Clinical measurement of myocardial infarct size. Modification of a method for the estimation of total creatine phosphokinase release after myocardial infarction

Abstract

A modified method for the measurement of total creatine phosphokinase release from venous blood samples taken four hourly after myocardial infarction was used in 43 patients. The fractional decay rate of enzyme activity was measured by a standardized method in each patient and accuracy of the calculation of total enzyme release was improved by allowance for individual variations in decay rate and discarding of data from which decay rates cannot be measured within confidence limits of less than 15%. Total enzyme release was greater in cases of transmural infarction than in patients with subendocardial infarction, and showed a good positive correlation with clinical indices of the extent of myocardial damage. As noted by previous workers, this method allows for the measurement of the rate as well as the extent of enzyme release, and so should prove useful in the clinical evaluation of therapeutic agent which might accelerate or retard the rate of myocardial necrosis in patients with acute myocardial infarction.