Objectives: It is not clear whether the presence and degree of chronic ischemic mitral regurgitation (IMR) in patients with left ventricular (LV) dysfunction are related to LV dysfunction, local LV remodeling or mitral valve deformation. We sought to establish the strongest determinants of IMR severity in patients with LV dysfunction and IMR.Methods: We prospectively performed transthoracic echocardiography for 135 patients (mean age = 60. 76 ± 9.69 years, 71.9% male) with LV dysfunction (ejection fraction ≤ 50%) and coronary artery disease (70% stenosis in ≥ 1 coronary artery and no myocardial infarction during the previous 16 days). Global and local LV remodeling and mitral deformity indices were measured. Using the vena contracta, MR severity was graded as no regurgitation; mild; moderate; and severe.Results: Mild regurgitation was found in 45 (33.3%) patients, moderate in 71 (52.6%), severe in 6 (4.4%), and no regurgitation in 13 (9.6%). By linear logistic multivariable analysis, the major echocardiographic determinants of MR severity were tenting area (TA), sphericity index (LV systolic length/width), and C-septal (distance between the leaflet coaptation and the septum). TA was best related to coaptation depth and annulus diameter. Mitral annular diameter was best correlated with left atrial surface area (r = 0.630, p < 0.001).Conclusion: TA was significantly correlated with annulus diameter and, along with sphericity index and C-septal, were the independent echocardiographic determinants of MR severity. These findings warrant consideration when performing mitral valve repairs for patients with IMR.