Inclusion Criteria:  Admission for acute decompensate chronic heart failure or acute de novo heart failure Ejection Fraction <40% Severe signs and symptoms of congestion with modified wet score ≥ 12 Spot urinary sodium excretion ≤ 70 mEq/L at 2 hours from first intravenous loop diuretic administration Systolic blood pressure ≥90 mmHg  Exclusion Criteria:  Reversible etiology of acute heart failure (including acute coronary syndromes, myocarditis, acute pulmonary embolism, acute rhythm disorders, severe organic valve disease) Cardiogenic shock at admission or sign of hypoperfusion needing inotropic agents or mechanical circulatory support. eGFR lower than 15 ml/min/1.73m2 or dialysis Pregnancy or breastfeeding