The novel calcium sensitizer levosimendan improves myocardial contractility without causing an increase in intracellular calcium and cyclic adenosine monophosphate concentrations. It also has a vasodilator action due to an opening of the adenosine triphosphate-sensitive potassium channels. In a double-blind clinical trial levosimendan was compared with dobutamine in 203 patients with severe low-output congestive heart failure. A 24-hour infusion of these inotropic drugs was administered to increase the cardiac output by at least 30% together with a decrease in the pulmonary capillary wedge pressure by ≥25%. The pre-defined hemodynamic improvement was achieved in 28% of patients receiving levosimendan compared to only 15% with dobutamine (p = 0.022). Levosimendan also reduced the 1- and 6-month mortality more than dobutamine (7.8 vs 17%, p = 0.045 and 26 vs 38%, p = 0.029, respectively). Levosimendan produced less myocardial ischemia and cardiac arrhythmias than dobutamine.
Calcium sensitizers offer a new therapeutic possibility in patients with decompensated low-output heart failure.