Levosimendan is a new calcium sensitizer with inodilatory properties. There is growing clinical experience with levosimendan given to cardiac surgical patients. The aim of this report was to evaluate the effects of perioperative use of levosimendan in surgical patients with high perioperative risk, compromised left ventricular (LV) function, or difficulties in weaning from cardiopulmonary bypass (CPB).Case series.Single-institution, university hospital.Patients undergoing cardiac surgery.Sixteen cardiac surgical patients received levosimendan infusion with a maximum duration of 29 hours. Eight were initiated preoperatively and 8 postoperatively. Coronary artery disease was the main operative indication in 10 of 16 cases, and 75% of the patients were high-risk patients.Continuous levosimendan infusion increased cardiac index significantly in both groups compared with preoperative baseline. Pulmonary capillary wedge pressure and systolic blood pressure did not change significantly. Norepinephrine and epinephrine were the most common concomitant vasoactive medications. Most importantly, weaning from CPB was successful in all patients even after failure to wean the patient with catecholamines. One high-risk patient in the preoperative group and 2 patients in the postoperative group died in the hospital. Another patient died during the 1-year follow-up.Levosimendan can be used for postoperative rescue therapy for patients difficult to wean from CPB. Also, elective preoperative initiation of levosimendan seems applicable to patients with high perioperative risk or compromised LV function.