Left ventricular assist device (LVAD) implantation is a widely accepted treatment for end-stage heart failure. Preoperative conditions and right ventricular dysfunction are determinant parameters that influence outcome. We investigated the effect of preoperative levosimendan treatment in LVAD patients with moderate right ventricular dysfunction and right ventricular dilatation. Twenty-one patients treated with LVADs were included in the study. Before surgery, patients received levosimendan infusion (0.1-0.2 μg/kg/min) for 48 hours. Hemodynamic parameters and NT-proBNP were evaluated before, during, and 24 hours after the end of levosimendan treatment. During levosimendan treatment, all patients demonstrated a significant improvement in cardiac index (p = 0.014), pulmonary pressure (p = 0.003), and central venous pressure (p = 0.016). The hemodynamic condition worsened 24 hours after the end of the treatment in patients who died because of right ventricular failure while it was s in patients who survived. NT-proBNP was significantly higher (6733 vs. 8797 pg/ml) (p = 0.019) in patients who died because of right ventricular failure after 24 hours of levosimendan treatment. During levosimendan treatment, the median NT-proBNP value in patients who survived decreased by 39%, whereas in patients who died there was an increase of 3% (p = 0.008) at 72 hours. A reduction in NT-proBNP to below 25% is a predictor of mortality with sensitivity of 100% and specificity of 70%. Levosimendan treatment improves preimplant hemodynamic performance and permits the identification of patients who will develop right ventricular failure.