This study is being done to evaluate the efficacy of levosimendan compared with placebo in reducing the co-primary endpoints of 30-day composite of all-cause death or use of mechanical assist device (IABP, LVAD or ECMO) or the composite event rate of all-cause death, perioperative MI, need for dialysis, or use of mechanical assist (IABP, LVAD or ECMO) in subjects with reduced ejection fraction undergoing cardiac surgery on CPB.