The pattern of contraction of the endocardial wall of the left ventricle in the right anterior oblique cineangiogram was studied by using a frame by frame radial technique and a fixed centroid without correction for rotation and translation motion during the cardiac cycle. Spatial defects of contraction were quantitated by measuring the shortening fraction of each radius and temporospatial defects by using a time-contraction integral. Twelve normal subjects were used as a basis for comparison. Thirty-two patients with isolated disease of the left anterior descending (LAD) coronary artery were divided into seven arbitrary clinicopathological subsets. Five subsets showed significant quantitative differences in contraction from the normal subjects but there was no significant difference between the subsets. They had a typical defect of contraction in the distal two thirds of the anterior wall, the apex and distal quarter of the inferior wall of the left ventricle. The subsets included: (1) patients who had undergone an anterior myocardial infarction and who had total occlusion of the LAD artery and a large anterior infarction on ECG; (2) patients with a previous classical myocardial infarction but with only 95% residual narrowing of the LAD; (3) patients with an anterior infarction and total occlusion of the LAD with return of the R waves in the anterior precordial leads; (4) patients with anterior infarction, LAD obstruction and left bundle branch block and (5) patients with anterior infarction but with early successful reperfusion with intracoronary streptokinase. Two other subsets, (1) patients with total obstruction of the LAD without a clinical myocardial infarction or (2) subtotal occlusion of the LAD without infarction, had mild left ventricular dysfunction at rest and did not differ significantly from normal.