[Estimation of the infarct size by two-dimensional echocardiography in cases with acute myocardial infarction].

We evaluated clinically the infarct size in addition to left ventricular end-diastolic and end-systolic volumes (EDV, ESV) and ejection fraction (EF) using two-dimensional echocardiography (2-D) and algorithms based on the modified Simpson's rule. EDV, ESV and EF obtained by 2-D and three algorithms were compared with those obtained by left ventriculography in 23 patients with various heart diseases. Correlation coefficients obtained by our and other two algorithms were 0.88, 0.88 and 0.90, respectively, for EDV and ESV (p less than 0.01), and 0.71, 0.60 and 0.84 for EF (p less than 0.01). Myocardial mass of the region showing asynergy (asynergic size) was calculated by the above-mentioned three methods and compared with peak serum CK values in 14 patients with acute myocardial infarction. The correlation coefficient between both values was 0.76 (p less than 0.01) by our algorithm and it was higher than by other two algorithms (0.37 and 0.70). The time course of changes in asynergic size in acute myocardial infarction was studied by the use of 2-D and our algorithm. Asynergic size was significantly larger on the day of the onset (24.9 +/- 2.9 ml, mean +/- SE) than the third (21.5 +/- 2.7 ml) and seventh day (20.7 +/- 3.0 ml) after the onset (p less than 0.01). These results suggest that one can make a quantitative and serial estimation of infarct size as well as left ventricular volume by 2-D and our modified model, and that our algorithm is suitable for the purpose.