Late estimation of myocardial infarct size by total creatine kinase nomogram

Abstract

We studied the possibility of enzymatic estimation of myocardial infarct size in patients late (between days 2 and 6) after the onset of acute myocardial infarction (AMI), in whom estimation of infarct size was difficult by analysis of time-activity curves of serum creatine kinase (CK) because of the lack of the enzymatic information during the initial 48 hours. Serial determinations of serum enzymes were performed in 32 patients within 6 hours after the onset of AMI and significantly close correlations were observed between cumulative total CK release and the cardiac fraction of lactate dehydrogenase isoenzyme (LDH 1) activities from day 2 to day 6 after the onset of AMI ( r = 0.863 to 0.870; p < 0.001). We developed a nomogram to estimate cumulative total CK release by serum LDH 1 activities obtained between days 2 and 6 after AMI and evaluated the reliability of the nomogram. Cumulative total CK release obtained from serial serum CK activities correlated closely with total CK release obtained from the nomogram in the second group of patients with AMI ( r = 0.923 to 0.946; n = 24; p < 0.001). Our total CK nomogram requiring few blood samples was useful in late estimation of infarct size in patients who were admitted to the hospital between days 2 and 6 after the onset of AMI.