Levosimendan Efficacy Assessment by Cardiopulmonary Exercise Test (CPET)

Eligible patients should have chronic HF (Heart Failure -class NYHA III or IV) in stable clinical conditions. Inclusion criteria were: left ejection fraction (EF) at echocardiography ≤35%, age ≥18 years old, peak VO2 <12 ml/min/kg measured by a CPET, a standard optimized therapy for HF that include ACE-inhibitors, ARBs (angiotensin II Receptor Blocker), aldosterone blocking agents (spironolactone), diuretics, and beta-blockers.

The exclusion criteria are: ongoing mechanical ventilation; recent or acute coronary syndromes; sustained ventricular tachycardia or ventricular fibrillation; severe aortic or mitral regurgitation, or known malfunctioning artificial heart valve; uncorrected obstructive valvular disease; hypertrophic obstructive cardiomyopathy; uncorrected thyroid disease.

Patients will be randomly assigned by means of prepared letters to the levosimendan or placebo group stratified by clinical centre in a 1:1 allocation using block randomization. The placebo infusion will be coloured identically to its respective active counterpart. Patients and investigators will be kept blinded to the treatment allocation for the entire duration of the trial. Study drug will be infused with an injection speed between 6 and 20 ml/min based on blood pressure, without a bolus, for 24 hours.

Medical history, physical examination and a blood sample examination will be recorded: NYHA class, BNP (Brain Natriuretic Peptide), haemoglobin, creatinine, blood urea nitrogen (BUN) will be recorded before and 24 hours after the drug infusion.

A two-dimensional standard echocardiography evaluation will be performed at the admission in the hospital.

A maximal CPET performed on a cycle ergometer (Sensor Medics Ergo 800S and V-max, Yorba-Linda, CA) with a personalized ramp aimed at achieving peak exercise in 10 minutes will be performed before and 24 hours after the drug infusion. Expiratory O2, CO2 (Carbon dioxide) and ventilation (VE) will be measured breath by breath. Peak VO2 (Carbon dioxide production) was considered to be the highest VO2 achieved during the exercise. A 12-lead electrocardiogram will be also recorded. Spirometry and DLCO measurements will be performed before ad 24-hours after the drug infusion. . DLCO will be measured by the single breath-constant expiratory flow technique