Inclusion Criteria:  Diagnosed with HF in line with the European Society of Cardiology (ESC) guidelines34; Left ventricular EF ≤35%; Undergoing cardiac surgery on CPB with an anticipated duration of >120 minutes; Age ≥18 years.  Exclusion Criteria:  Incapacitated; Emergency operation; Need for moderate or high dosages of intravenous inotropic support (>4 gamma dobutamine or dopamine) and/or vasopression; Severe tricuspid regurgitation; Daily use of nitroglycerine or isosorbide dinitrate; Use of alpha blockers; Being heparin-induced thrombocytopenia (HIT) positive and citrate regional anticoagulation is unavailable as an alternative anticoagulation method; Platelet count <20,000/μL.