Myocardial efficiency during levosimendan infusion in congestive heart failure

Aims: Levosimendan, a novel calcium-dependent calcium sensitizer of the myo cardial contractile proteins, also enhances diastolic relaxation and induce s peripheral vasodilation by opening potassium channels. To assess the comb ined energetical effects of levosimendan infusion in vivo, we performed pos itron emission tomography in patients with decompensated chronic heart fail ure. Methods and Results: Eight hospitalized patients with New York Heart Associ ation functional class III or IV heart failure received levosimendan or pla cebo intravenously in a randomized double-blind cross-over study, During st eady-state, dynamic positron emission tomography with [C-11]acetate was use d to assess myocardial oxygen consumption and [O-15]H2O to measure myocardi al blood flow. Cardiac performance and dimensions were assessed by pulmonar y artery catheterization and echocardiography, Compared with healthy volunt eers, myocardial oxygen consumption during placebo was elevated in the righ t ventricle but comparable in the left ventricle, During administration of levosimendan, cardiac output increased by 32% (P = .002) mainly because of higher stroke volume. Coronary, pulmonary, and systemic vascular resistance values were significantly reduced. Mean myocardial blood flow increased fr om 0.76 to 1.02 mL/min/g (P = .033), Levosimendan was neutral on myocardial oxygen consumption and left ventricular efficiency but it improved right v entricular mechanical efficiency by 24% (P = .012), Conclusions: Levosimendan has an energetically favorable short-term profile in the treatment of congestive heart failure, It enhances cardiac output w ithout oxygen wasting, particularly by improving efficiency in the right ve ntricle.