Levosimendan In Ambulatory Heart Failure Patients

Inclusion Criteria: * Informed consent obtained before any trial activities * Male or female, age ≥ 18 years at the time of signing informed consent * Left ventricle ejection fraction ≤ 35% * Hospitalization due to worsening of HF within the last 3 months * New York Heart Association functional class III or outpatient IV * Individually optimized pharmacotherapy, based on the current European Society of Cardiology recommendations, stable for at least 1 month prior to randomization, according to the knowledge and experience of the qualifying clinician * Distance covered in six-minute walk test \<350m OR NTproBNP concentration ≥ 1000 pg/mL * In the opinion of the Investigator, the patient does not currently require hospitalization * Patient protected with an implantable device capable of terminating life-threatening arrhythmias and conduction disturbances (ICD or cardiac resynchronisation therapy-D/P), if indicated and the patient consents to implantation. Exclusion Criteria: * Known or suspected hypersensitivity to trial products or related products, * Restrictive or hypertrophic cardiomyopathy, uncorrected severe valvular disease, potentially reversible cause of HF * Hypotension with symptoms of tissue hypoperfusion * Uncontrolled hypertension * Planned revascularization or other surgical treatment of HF within the next year * Advanced chronic kidney disease * Features of liver damage * Severe chronic lung disease with features of respiratory distress or severe abnormal spirometry or home oxygen treatment * Accompanying chronic diseases with poor prognosis * Paroxysmal supraventricular tachycardia, paroxysmal ventricular tachycardia, torsade de pointes, advanced atrioventricular blocks within one month prior to screening * Receipt of any investigational product within 30 days before screening visit * Any disorder, which in the investigator's opinion may jeopardise subject's safety or compliance with the study protocol and procedures