The purpose of this study was to evaluate the characteristics of mitral annular motion during diastole in 28 normal subjects, 40 patients with prior myocardial infarction (MI), and 23 patients with coronary artery disease but without prior MI. Mitral annular motion during diastole was obtained from the apex by M-mode echocardiography at the posterior wall of the left ventricle. Determinants of mitral annular excursion during early (MAE-E) and late diastole (MAE-L) were investigated in all subjects. Differences in the MAE-E, MAE-L, and the MAE-L:MAE-E ratio were compared among the three patient groups. The Doppler-derived transmitral flow velocity-time integral during early (EI) and late (AI) diastole and mitral annular excursions during diastole were obtained in 55 other patients with a prior MI and in 29 healthy volunteers. The relationships between the MAE-L:MAE-E ratio and AI:EI ratio in these two groups were studied. The MAE-E was determined mainly by heart rate and left ventricular ejection fraction (LVEF). The MAE-L was determined only by age. The magnitude of MAE-E was significantly less in patients with a prior MI than in normal subjects (P < 0.01). However, the MAE-L did not differ among the three groups. The MAE-L:MAE-E was higher in patients with a prior MI than in normal subjects (P < 0.05), and was significantly correlated with AI:EI in healthy volunteers (r = 0.65, P < 0.001) and in patients with a prior MI (r = 0.50, P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)