Quantitative detection of regional left ventricular contraction abnormalities by 2-dimensional echocardiography. Comparison of myocardial thickening and thinning and endocardial motion in a canine model.

Myocardial infarction (MI) was produced in 27 dogs by ligation of the left anterior descending coronary artery. Two-dimensional (2-D) echocardiograms were performed through the closed chest before and serially after coronary ligation, in both the acute and healing stages of MI. Two-dimensional echocardiographic studies performed before the animals were killed were analyzed for left ventricular (LV) contraction defects by 2 algorithms--1 involving systolic myocardial thickening and thinning and the other by determining the extent of endocardial motion to derive cavity area shrinkage. Using the thickening algorithm, myocardial dysfunction was detected in 93% of the animals with MI; with the area shrinkage method, contraction abnormalities were detected in 96% of the animals with MI. When the heart was divided from base to apex into 3 short-axis sections, the thickening algorithm showed a trend toward better identification of normal regions than the area shrinkage algorithm. However, in predicting the circumferential extent of MI, the thickening-thinning method of analysis showed no advantage over the endocardial motion method (r = 0.77, standard error of the estimate = 0.16 versus r = 0.76, standard error of the estimate [SEE] = 0.16; p = not significant [NS]). These observations support the concept that either algorithm can be used effectively to detect the presence and quantify the circumferential extent of MI.