Primary organ failure after heart transplantation is a severe complication generally related to prolonged ischemia time, poor quality of the organ, or rejection. Ca(2+) sensitisers increase cardiac contractility without altering intracellular Ca(2+) levels. Our aim was to evaluate the influence of levosimendan in the therapy of primary failure after heart transplantation. Five patients presenting with reduced ejection fraction (EF<30%) and high dosed catecholamines after heart transplantation were treated with levosimendan (Simdax, Abbot GesmbH, Vienna, Austria) in a 24-hour continuous infusion (0.10 microg/kg*min) postoperatively. We assessed hemodynamic measurements including MAP, CVP, and PAP as well as heart function. Pharmacologic support with catecholamines could be halved at 24 hours and terminated in four of the patients 72 hours after levosimendan administration. Hemodynamics (MAP 70 +/- 11 vs 85 +/- 6 mm Hg; CI 2.5 +/- 0.4 vs 3.6 +/- 0.4 L/min/m(2)) and EF (28 +/- 10 vs 54 +/- 4%) improved at 48 hours after treatment. Acute graft failure after cardiac transplantation is associated with poor short- and long-term outcomes. Among our patients, levosimendan reduced the need for catecholamine support as well as improved ventricular performance.