In 238 patients with acute myocardial infarction studied during intracoronary streptokinase therapy, the circumferential extent of left ventricular hypokinesis was measured by 5 methods and correlated with the location of the infarct-related coronary artery segment and with 1-year survival. Of the 5 methods, 1 focused only on the infarct region, and 4 varied in the complexity of the noise filter. Hypokinetic segment length measurements by all 5 methods correlated significantly with the location of occlusion along the left anterior descending coronary artery. No method yielded measurements that correlated with occlusion location along the right coronary artery. Measurements by all methods correlated significantly with survival, but the method that focused on the infarct region performed least well. Thus, the circumferential extent of hypokinesis in patients with acute myocardial infarction is greater for proximal than mid- or distal occlusions of the left anterior descending but not the right coronary artery. Survival is influenced by the function of periinfarct and noninfarct regions and by the function of the infarct region. Complex noise filters provide no advantage over simpler filters in measuring the extent of hypokinesis.