Dopamine in Acute Decompensated Heart Failure (DAD-HF) Trial

Inclusion Criteria: * patients with New York Heart Association (NYHA) functional class IV heart failure according to the American Heart Association (AHA) classification, namely dyspnea on minimal exertion or rest dyspnea, orthopnea, and paroxysmal nocturnal dyspnea * signs of congestion (third heart sound or pulmonary rales on physical examination) * pulmonary congestion on chest x-ray * serum B-type natriuretic peptide levels \> 400 pg/ml or NT-proBNP \> 1500 pg/ml * echocardiographic documentation of systolic or diastolic dysfunction * all candidate patients must be: * Age \>18 years old * on medical therapy with an ACE-inhibitor and/or a β-blocker * experiencing an acute decompensation of known chronic HF * Having baseline oxygen saturation \<90% on admission arterial blood gas Exclusion Criteria: * the investigators will exclude patients with: * acute de novo HF * severe renal failure (serum creatinine \> 200 μmol/L or GFR \< 30 ml/min/1.73m2) * admission systolic blood pressure \< 90 mm Hg * severe valvular disease * known adverse reactions to furosemide or dopamine * HF secondary to congenital heart disease * a scheduled procedure with a need for IV contrast dye * a scheduled cardiac surgery within 6 months