Rapid initiation of the four pillars of heart failure therapy can transform outcomes in hospitalized patients with decompensated heart failure with reduced ejection fraction (HFrEF). At the European Society of Cardiology (ESC) 2025, a prospective observational cohort of 203 HFrEF patients was evaluated to assess hemodynamic and biological responses to inpatient therapy.

Group A (n=126) had no prior exposure to the four pillars (ACE inhibitors/ARBs/ARNI, beta-blockers, MRAs, SGLT2 inhibitors), whereas Group B (n=77) received therapy optimization. Across hospitalization, both groups experienced notable reductions in systolic and diastolic blood pressure and heart rate, alongside improvements in NYHA functional class. Serum creatinine, sodium, and potassium remained stable, indicating treatment safety. Use of MRAs and SGLT2 inhibitors increased significantly in Group B. No differences were observed in 30-day mortality. 

These findings underscore that early, aggressive, guideline-directed medical therapy can rapidly improve hemodynamic parameters, functional capacity, and clinical outcomes in decompensated HFrEF without compromising safety, highlighting its importance for in-hospital management strategies.