Acute decompensated heart failure significantly contributed to the damage of target organs and provided poor outcomes. In-hospital mortality and post-discharge outcomes have not been reduced by current treatment such as diuretics and vasodilators. Serelaxin is recombinant form of naturally occurring peptide relaxin-2 which is produced in a woman’s body at the first trimester of pregnancy. In RELAX-AHF study in patients with acute heart failure serelaxin demonstrated positive dynamics on symptoms of heart failure and reduced cardiovascular and all-cause mortality compared with standard therapy. Catheterization of right chambers in the study to assess haemodynamic effects of serelaxin demonstrated decrease of RAP, RVP systemic/pulmonary vascular resistance while increase creatinine clearance but has no impact on cardiac index. Clinical trials on serelaxin enroll patients with acute heart failure, eGFR 30—75 mL/min/1,73 m2, normal or high blood pressure and pulmonary congestion.