Extension of hypokinesia into angiographically perfused myocardium in patients with acute infarction

University of Washington, Seattle 98195.

OBJECTIVE. This study was performed to determine whether left ventricular hypokinesia due to acute myocardial infarction lies between the site of coronary artery occlusion and the end of the infarct-related artery in patients. BACKGROUND. Normalizing for the size of the risk region reduces variability in measuring infarct size in experimental studies. The ability to gauge the size of the region at risk of becoming dysfunctional may help reduce variability in measuring regional hypokinesia due to acute myocardial infarction. METHODS. Angiograms of 84 patients with acute infarction due to isolated stenosis of the right coronary artery (n = 40) or the left anterior descending coronary artery (n = 44) were analyzed. The location and length of the segment with hypokinesia more severe than -1 or -2 SD below the normal mean were determined by the centerline method. The risk region was defined as the left ventricular contour between the site of the occlusion and the end of the infarct-related artery on the angiogram. RESULTS. The segment with hypokinesia below -1 SD was longer than the risk region in 52% of patients with occlusion of the left anterior descending coronary artery, more frequently (p < 0.01) than in right coronary artery occlusion (22%), owing to extension of hypokinesia beyond the distal end of the artery. Extension of severe hypokinesia (below -2 SD) beyond the risk region occurred in 33% of patients with an anterior infarct and in 9% of patients with an inferior infarct. CONCLUSIONS. The size of the risk region cannot be assessed accurately from coronary angiography.