Subjective interpretation of angiographic left ventricular regional wall motion is routinely performed with knowledge of the location and extent of coronary artery stenosis. We studied 100 patients with coronary artery disease in order to determine the accuracy of such wall motion assessment relative to a more objective standard based upon computer-assisted left ventricular (LV) ejection fraction and end-systolic fractional shortening referenced to the end-diastolic area centroid. Only 379 of 700 (54%) region-by-region comparisons of wall motion were in precise agreement. Computer-assisted wall motion analysis correlated significantly better with ejection fraction than did subjective analysis (r = 0.82 vs r = 0.61, p less than 0.002). In 56 patients, in whom major discordance was noted, subjective assessment of wall motion correlated significantly better with the presence of coronary artery stenosis (p less than 0.05), but objective assessment correlated significantly better with ejection fraction in these same patients (p less than 0.02). These data suggest that the accuracy of subjective assessment of regional wall motion, relative to global ejection fraction, can be adversely biased by knowledge of the patient's coronary anatomy. Because of the inherently reproducible nature of the algorithmic process, and in light of the better correlation with global function, computer-assisted analysis of regional wall motion might be preferable to conventional subjective assessment.