SOCRATES-REDUCED enrolled 456 patients with LV ejection fraction (LVEF) < 45% and a recent episode of HF decompensation, defined by worsening HF symptoms requiring hospitalization or outpatient administration of intravenous diuretics, signs of congestion, and elevated NP levels (BNP ≥ 300 ng/L or NT-proBNP ≥ 1000 ng/L; for patients in atrial fibrillation [AF], BNP ≥ 500 ng/L or NT-proBNP ≥ 1600 ng/L), excluding those with eGFR < 30 mL/min/1.73 m2 and systolic blood pressure < 110 or ≥ 160 mmHg. Here, NPPB is linked to hydrops fetalis.