The effect of exercise on the displacement of the atrioventricular (AV) plane was studied by echocardiography (echo) in 48 patients with stable angina pectoris without prior myocardial infarction and 20 age-matched healthy subjects. Echo was performed at rest, immediately after and 10 and 30 min after the test. The patients also underwent thallium stress scintigraphy and coronary angiography. From the apical four- and two-chamber views, the atrioventricular plane displacement (AVPD) during the cardiac cycle was recorded at four sites corresponding to the septal, anterior, lateral and posterior walls of the left ventricle and a mean value was calculated (AV-mean). The healthy subjects and patients had almost the same AVPD at all the sites at rest (AV-mean of 14.5 and 14.2 mm respectively). Immediately post-exercise the healthy subjects showed a significant (P less than 0.001) and equally distributed increase in the AVPD at all the sites with an AV-mean value of 19.2 mm. In most of the patients with angiographically confirmed coronary artery disease (CAD), there was a reversible decrease of AVPD (greater than or equal to 3 mm) at one or more of the AV plane sites. The overall sensitivity and specificity were 80% and 100% respectively in identifying CAD patients. The changes correlated well with the reversible ischaemic changes on the thallium scan (sensitivity, 88%, and specificity, 83%). A generalized exercise-induced decrease in AVPD at all the recorded sites had a high specificity (91%) in detecting patients with three-vessel disease.(ABSTRACT TRUNCATED AT 250 WORDS)