Value and limitations of two-dimensional echocardiography in predicting myocardial infarct size

To investigate the quantitative relations between the severity of regional wall motion abnormalities and segmental infarct size and between the severity of overall left ventricular dysfunction and global infarct size, a clinicopathologic study was undertaken of 30 patients who had a 2-dimensional (2-D) echocardiogram within 7 days before death. The severity of regional wall motion abnormalities was graded for each segment with a 2-D echocardiographic 14-segment model. The severity of global left ventricular dysfunction was calculated as the mean of the visualized regional wall motion scores. On pathologic examination of autopsy specimens, segmental infarct size was estimated as a percentage of the segmental cross-sectional area. The global infarct size was expressed as a percentage of the total left ventricular mass. At the segmental level, regional wall motion score was positively correlated (r = 0.53) with the segmental infarct size. The sensitivity and specificity of detecting infarcted segments by abnormal wall motion scores were 81 and 71%, respectively. All dyskinetic segments revealed infarct size of greater than or equal to 10%. The wall motion score index was positively correlated (r = 0.52) with the global infarct size. The mean global infarct size was 7% for the 8 patients with a wall motion score index of less than 2, which was significantly lower than the mean of 27% for the 22 patients with a wall motion score index of greater than or equal to 2 (p less than 0.001). A 2-D echocardiogram is sensitive and specific in detecting infarcted segments and can be useful in quantitating myocardial damage after myocardial infarction.