Decreased left ventricle ejection fraction (LVEF) is a predictor of poor late outcome in patients with mitral regurgitation (MR). The relationship between pre-operative forward stroke volume (SV) and right heart parameters and perioperative outcome in patients with MR has been little studied.Forty patients with severe organic MR, unsuitable for mitral valve repair, who underwent mitral valve replacement (MVR) were included in the study (50% men, average age 61 +/- 9 years). Exclusion criteria were: aortic valve disease, coronary artery disease, rethoracotomy, stroke, infection or significant perioperative bleeding. Pre-operative detailed echocardiographic examination was performed. The end-point was post-operative prolonged intensive care unit (ICU) stay of more than three days because of the need for inotropic support.Pre-operative NYHA class was 2.6 +/- 0.4, mean right ventricular end-diastolic diameter (RVEDD) was 28.7 +/- 4 mm, TAPSE was 20 +/- 4 mm, mean right ventricular systolic pressure (RVSP) was 38 +/- 13 mm Hg, left ventricular end-systolic diameter was 43.5 +/- 11 mm, left ventricular end-diastolic diameter was 60 +/- 11 mm, left ventricular end-diastolic volume (Simpson) was 155 +/- 47 mL, LVEF was 55 +/- 11%, mean regurgitation fraction was 58% and forward SV (measured by Doppler) was 35 +/- +/- 11 mL. All patients survived the operation. Mean ICU stay was 3.2 +/- 2.9 days (range 1-10 days), mean TISS-28 was 623 +/- 293 and mean NEMS 151 +/- 85. By univariate analysis, ICU stay was significantly longer in patients in higher pre-operative NYHA (p = 0.04), lower LVEF (p = 0.01), lower forward SV (p = 0.001) higher RF (p = 0.01), pre-operative right ventricular dilatation (p = 0.04), higher RVSP (p = 0.006) and right ventricular dysfunction (p = 0.04). By multivariate analysis, forward SV (p = 0.002, b = -0.45) and RVEDD (p = 0.02, b = 0.31) were independent predictors for prolonged ICU stay.Pre-operative forward stroke volume and right ventricle size are predictors of the perioperative hemodynamic status in patients with mitral regurgitation undergoing MVR.