• Hospital admission with diagnosis of acute heart failure assessed by clinical signs and symptoms of congestion and radiographic, biological tests (if admitted with acute coronary syndrome, required at least Killip class II or clear evidence of congestion on admission assessed by chest x-ray or lung ultrasound and/or pulmonary congestion requiring intravenous treatment)

• Female or male patients ≥ 18 years old

• At randomization:

‣ Systolic blood pressure \> 90 mmHg (at least 2 measurements on 2 different occasions) and

⁃ Heart rate ≥ 60 bpm (at least 2 measurements on 2 different occasions) and

⁃ Serum potassium ≤ 5.0 mmol/L

• Left ventricular ejection fraction (LVEF) ≤ 40% assessed locally by Simpson's Biplane method via echocardiography (if multiple LVEF measurements, the last one performed prior to randomization should be considered as the qualifying measurement)

• Persistent congestion at the time of randomization with pre-discharge NT-proBNP ≥ 1500 ng/L

• HFrEF medications at randomization:

‣ ≤ ¼ RASi/ARNi target dose and

⁃ ≤ ¼ beta-blocker target dose and

⁃ ≤ ½ MRA dose

• Obtained written informed consent form