Background: Levosimendan is a new calcium sensitizer with positive inotropic properties. Cardiac power output (CPO) has been shown to be instrumental in the diagnosis of cardiogenic shock (CS) and is an important determinant of outcomes. Aims: To evaluate the haemodynamic effects of levosimendan compared to dobutamine in acute myocardial infarction (AMI) patients revascularised by primary percutaneous coronary intervention (PCI), who developed CS. Methods and results: Twenty two consecutive AMI patients revascularised by PCI, who developed CS, were randomly assigned to levosimendan (24 mu g kg(-1) bolus plus 24-h continuous infusion 0,1 mu g kg(-1) min(-1)) or dobutamine (initial dose 5 mu g kg(-1) min(-1), with a maximum dose adjustment in order to reach the desired haemodynamic effect). Evaluations were performed from baseline to 30 h. The primary end-point was an increase >= 30% in CPO, after 24 h of therapy. The baseline clinical and haemodynamic characteristics were similar in both groups. Levosimendan had a consistently better effect on CPO than dobutamine, while the decrease in PCWP was similar. Conclusion: The primary objective of our study was achieved better by the end of the 24 h infusion of levosimendan than by dobutamine. (c) 2006 European Society of Cardiology. Published by Elsevier B.V. All rights reserved.