Inclusion Criteria:  Age 18 years or older AHF diagnosis, defined as rapid onset or worsening of symptoms and/or signs of HF. According to a recently proposed new definition, HF is a clinical syndrome with current or prior Symptoms and or signs caused by a structural and/or functional cardiac abnormality (as determined by EF <50%, abnormal cardiac chamber enlargement, E/E' >15, moderate/severe ventricular hypertrophy or moderate/severe valvular obstructive or regurgitant lesion) and corroborated by at least one of the following: Elevated natriuretic peptide levels ; Objective evidence of cardiogenic pulmonary or systemic congestion by diagnostic modalities such as imaging (e.g. by chest X-ray or elevated filling pressures by echocardiography) or haemodynamic measurement (e.g. right heart catheterization, pulmonary artery catheter) at rest or with provocation (e.g. exercise). Intravenous SNP treatment  Exclusion Criteria:  Age <18 years old AHF after cardiac surgery AHF complicated by cardiogenic shock requiring high dosage (defined as inotropic score >10) vasoactive agents and/or short-term extracorporeal life support (i.e. VA-ECMO, Impella). Inotropic score (IS) calculated as: dopamine dose (μg/kg/min) + dobutamine dose (μg/kg/min) + 100 × epinephrine dose (μg/kg/min) + 100 × norepinephrine dose (μg/kg/min) + 10 × phosphodiesterase 3 inhibitor dose (μg/kg/min).