Resumption of Atrioventricular Conduction by Levosimendan After Radiofrequency Ablation of the AV Node:. Does Levosimendan Have Potential as Medical Therapy in Atrioventricular Conduction Disease?

Effect of Levosimendan and Milrinone on Regional Myocardial Ischemia/Reperfusion-Induced Arrhythmias in Dogs

Phosphodiesterase inhibitors as inodilators in heart failure are associated with promotion of arrhythmias. Calcium sensitizers have been proposed for the treatment of severe decompensated heart failure. The effect of levosimendan, a calcium sensitizer, and milrinone, a phosphodiesterase inhibitor, on ventricular arrhythmias was compared in a model of acute regional myocardial ischemia and reperfusion. The left anterior descending coronary artery in dogs was occluded for 25 minutes, followed by reperfusion. The 2 drugs were administered in a hemodynamically equieffective dose (0.1 μmol/kg) 10 minutes before coronary occlusion. Levosimendan, but not milrinone, significantly attenuated the pronounced increase in the number of ventricular premature beats (-63%), tachycardia (-50%), fibrillation (-70%), and inhomogeneity of ventricular electrical activation. Levosimendan significantly improved the overall survival rate. Levosimendan has a more beneficial profile than milrinone regarding the development of ventricular arrhythmias during and after regional myocardial ischemia

Cardiovascular effects of levosimendan in the early stages of endotoxemia

Sepsis-associated myocardial depression is associated with calcium desensitization and adrenergic uncoupling. We conducted a prospective randomized investigation on the effects of the calcium sensitizer, levosimendan, on hemodynamics, myocardial blood flow, and myocardial lactate metabolism during porcine endotoxemia. Twelve pigs were studied. Oxygen consumption was measured by indirect calorimetry, and myocardial blood flow was measured by retrograde thermodilution. Pulmonary, arterial, and venous indwelling catheters allowed measurements of cardiac output, vascular pressures, and blood sampling. Fluids were given at an average of 15 mL . kg . h. After baseline measurements (0 min), an infusion of Escherichia coli LPS (2 microg . kg . min) was started in all animals. Beginning at 100 min, six animals received levosimendan (50 microg . kg . h), whereas six control animals received placebo. The study lasted for 300 min. All animals responded to endotoxin with pulmonary hypertension, a transient decrease in cardiac output, tachycardia, and systemic hypotension. Levosimendan infusion decreased systemic vascular resistance (P = 0.001), coronary vascular resistance (P = 0.004), and mean arterial (P < 0.001) and coronary perfusion pressures (P < 0.001), whereas pulmonary hypertension was unaffected. Heart rate progressively increased in both groups and was significantly higher in the levosimendan group (P = 0.048). Myocardial blood flow remained unchanged in both groups; however, 80 min after the start of levosimendan infusion, left ventricular myocardial hypoxia ensued, as evidenced by a negative myocardial lactate gradient (P = 0.01). Two control and five levosimendan animals died before the end of the study. Early administration of levosimendan during porcine endotoxemia increased heart rate, caused arterial vasodilation, and decreased coronary perfusion pressure, resulting in myocardial hypoxia.

Ca2+-sensitisers--a promising option to treat heart failure?

Because the number of transplants is still fewer than the number of patients waiting for a donor organ, new concepts of therapy are needed that allow patients to bridge the time gap until heart transplantation or even to improve symptoms while on treatment. Ca(2+)-sensitisers are agents that directly influence myofilaments and/or the cross-bridge-cycle. Depending on the molecular mechanisms underlying their action, Ca(2+)-sensitisers have been divided into three classes. While, a number of Ca(2+)-sensitising drugs have been described, currently only the Ca(2+)-sensitisers pimobendan and levosimendan are in clinical use. This review provides a survey on the molecular mechanisms and the therapeutic effectiveness of Ca(2+)-sensitisers for the treatment of human heart failure.