['Our aim was to define the anatomy of the coronary sinus (CS) by venography. These measurements are essential in the selection of physical characteristics of percutaneous annuloplasty devices for mitral regurgitation (MR).', 'Clinical trials of percutaneous annuloplasty of the CS for MR are now underway. Although the CS is in close proximity to the mitral annulus, there is as yet no published quantitative data defining the magnitude of change in CS dimensions in MR, and how these changes might reflect the magnitude of MR.', 'We studied 57 patients (27 patients with MR and 30 patients with no MR) who were referred for cardiac resynchronization therapy and underwent CS venography. Echocardiography was used to assess the degree of MR, cardiac dimensions, and right heart filling pressures. The diameter of the ostial and proximal CS and perimeter of the CS-great cardiac vein (GCV) were assessed by quantitative coronary analysis.', 'Patients with MR had a larger ostial CS diameter (19.4+/-3.9 mm vs. 16.9+/-4.6 mm, P=0.02) and proximal CS diameter (8.2+/-1.7 mm vs. 7.4+/-2.3 mm, P=0.05) and larger CS-GCV perimeter (104.4+/-15.6 mm vs. 86.5+/-15.3 mm, P=0.005) compared with patients with no MR. The CS-GCV perimeter is positively correlated to the severity of MR (P=0.02) and pulmonary artery pressure (r=0.32, P<0.05).'] Is coronary sinus dilated and outwardly displaced in patients with mitral regurgitation : quantitative angiographic analysis?