Inclusion Criteria:  Age ≥ 18 years old. HF diagnosis according to European Society of Cardiology LVEF≤50% (systolic HF). Patients receiving oral standard medication for chronic HF. Iron status evaluated in the last 3 months. Written informed consent.  Exclusion Criteria:  Age<18 years old. Intravenous or oral iron administration or under treatment with ESA (erythropoiesis-stimulating agents) in the previous 3 months. Planned cardiac resynchronization therapy (CRT), revascularization and other major interventions including heart transplant or left ventricular assist device (LVAD) implantation in the next 3 months in patients with ID. Planned uptitration of guideline-mandatory HF-modifying drugs in the next 3 months (except iron repletion) in patients with ID. Moderate or severe anaemia (Hb<11 g/dL). The patient is unable or unwilling to give the informed consent to participate. Unstable patients with signs of fluid overload or low cardiac output at the moment of enrollment. Life expectancy less than 1 year (excluding HF). The patient is considered not to be an adequate candidate for this study according to the decision of the local investigator.