The clinical, electrocardiographic, and angiographic findings of 90 patients, whose RAO 30° left ventriculograms showed segmental early relaxation (SER), were compared with those of 100 patients without SER. There were no signifi cant differences in age and sex distribution or in clinical and coronary angio graphic findings between the two groups. There was, however, a significantly lower prevalence of pathologic Q or QS patterns in the anterior leads of the ECG in the group with SER. SER occurred more frequently in segments with well-preserved systolic contraction and was confined to the anterolateral seg ments in the great majority of the patients (80%). An inverse correlation was found between SER and geographically related critical coronary artery stenosis.