P>Levosimendan is a 'Ca2+sensitiser', which exerts its inotropic effect by increasing the affinity of troponin C for Ca2+, directly stabilising the Ca2+-induced conformation of troponin C. It leads to a positive inotropic effect without impairing diastolic relaxation and causing cytosolic Ca2+ ion overload, which might result in cardiac myocyte dysfunction, arrhythmias and cell death. Levosimendan may also have significant anti-inflammatory properties. Data from various studies suggest that levosimendan might have anti-arrhythmic effects, although the outcome of clinical trials on the effect of this agent in (for example) atrial fibrillation (AF) remains controversial. Currently, on the basis of available data, it is especially worth emphasising the potential role of this drug in the termination of AF after cardiac surgery, which significantly influences early- and long-term morbidity and mortality. This review considers the putative anti-arrhythmic properties of levosimendan and discusses the potential clinical application of such a drug.