Contributions of late diastolic filling (slow filling and atrial systolic phases) to total filling volume in both global and regional left ventricle were analyzed using radionuclide techniques in 21 patients with isolated left anterior descending coronary artery disease without previous myocardial infarction. A computer program subdivided the image of the left ventricle into four regions at a geometric center of the area. The time-activity and its first-derivative curves of the global and regional left ventricles were computed. In the global left ventricle, the percent contributions of late diastolic filling to total filling volume were significantly increased in patients with one-vessel disease than in control subjects (20±5%, 28±4%; p<0.001). In the regional left ventricle, in patients with one-vessel disease, the percent contributions of late diastolic filling to total filling volume were significantly increased in the septal (25±5%, 34±8%; p<0.001) and in the apical regions (21±4%, 28±4%; p<0.001) which were perfused by stenosed vessel. In contrast, there were no significant differences in this value between the two groups in the normally perfused lateral region (226%, 255%; p=NS). These results indicate that the late diastolic filling makes a larger contribution to the left ventricular filling in the affected regions than in the normally perfused regions, and that the increased late diastolic filling in the affected regions are the cause for the increased late diastolic filling in the global left ventricle in patients with one-vessel disease.