To determine the usefulness of the standard echocardiogram in the diagnosis of left anterior descending coronary artery disease proximal or distal to the first septal branch, coronary arteriograms and echocardiograms were performed in 77 patients with a chest pain syndrome. Seventy-nine percent of patients with proximal disease (15 of 19) had an abnormal septal motion measured as a posterior wall/interventricular septal (PW/IVS) excursion ratio greater than or equal to 2.5 compared with 10% of patients with distal disease (2 of 20) who had abnormal septal motion. Only 5% of patients without obstructive disease of the left anterior descending coronary artery (2 of 38) had abnormal septal motion. Proximal disease was found in 79% with abnormal septal motion in the echocardiogram (15 of 19) but in only 7% of patients with normal septal motion (4 of 58). Therefore, abnormal septal motion as measured by the PW/IVS excursion ratio in the echocardiogram is a useful index for the diagnosis of disease of the left anterior descending coronary artery when that disease is proximal to the first septal branch.