Angiographic study of the motion of the septal and left marginal arteries was performed in patients with restriction in ventricular diastolic filling in order to separate patients with constrictive pericarditis from those with restrictive cardiomyopathy. Twelve patients with constrictive pericarditis (group I) and 10 patients with restrictive cardiomyopathy (group II) were evaluated and compared with 21 patients with normal coronary angiograms (group III). The displacement of the septal arteries (23 ± 2.04 mm) was abnormally exaggerated in group I and normal (9 ± 0.81 mm) in groups II and III. The displacement of the left marginal arteries as seen by the "corrugating index" was similar in all groups. We conclude that study of the displacement of the septal arteries is a useful angiographic sign that helps to separate constrictive pericarditis from restrictive cardiomyopathy and normals. © 1984.