Medical Support and Surgery of the Failing Heart: Levosimendan

Correspondence: Wolfgang Toller, M.D. Department of Anesthesiology and Intensive Care Medicine Medical University of Graz, Auenbruggerplatz 29 8036 Graz, Austria Email: wolfgang.toller@meduni-graz.at ous causes including pre-existing disease, incomplete repair or revascularization, reperfusion injury, inflammatory responses and postischemic dysfunction, e.g. myocardial stunning. Patients with myocardial contractile dysfunction frequently require transient intraand postoperative inotropic support to facilitate separation from cardiopulmonary bypass and to maintain adequate organ perfusion and cardiac output until recovery occurs usually within 48–72 hours. Typically, catecholamines and phosphodiesterase III inhibitors are administered in the perioperative period in patients with severely compromised myocardial performance although the value of such a treatment is uncertain. While short-term support of the myocardium with such drugs frequently helps overcome, stabilise and improve a compromised contractile dysfunction, this treatment has been repeatedly accounted for the production of severe sideeffects, including production of myocardial ischaemia, cardiac arrhythmias and possibly increases in mortality (1). A potential reason for these unwarranted effects may be related to the mechanism of action of these drugs in the myocardium, i.e. increasing intracellular calcium concentrations in myocytes with a parallel increase of myocardial oxygen consumption and arrhythmogenesis. As, on the other hand, beta-adrenoceptor antagonists have been demonstrated to improve survival in high-risk cardiac patients (2) and therefore frequently are part of standard therapy preoperatively, it is not surprising that intense research has been performed in order to discover new substances with positive inotropic action devoid of the above mentioned side-effects and compatible with standard drugs taken by these patients. Levosimendan is a member of such a new group of positive inotropic drugs that stimulate myocardial contraction through a different mechanism as compared to standard positive inotropic drugs (3). Although the effects of levosimendan currently have mainly been investigated in settings other than the perioperative, inInTroDUCTIon