Vericiguat and Reverse Remodeling Indices in Heart Failure

The goal of this clinical trial is to investigate how vericiguat benefits adults with stable heart failure with reduced ejection fraction (HFrEF) who are already receiving guideline-directed medical therapy. The main questions are: * Does vericiguat improve right ventricular systolic function, measured by fractional area change (FAC)? * Does vericiguat favourably influence myocardial remodeling, fibrosis, angiogenesis, inflammation, metabolism, renal function, and hematologic balance? * Do genetic and oxidative stress profiles modify treatment response? Researchers will compare a group receiving vericiguat plus usual care with a group receiving usual care alone to assess structural, functional, and biomarker changes over 12 months. Participants will: * Have blood drawn at baseline and follow-up visits for biomarker, metabolomic, genetic, transcriptomic, and hematologic analyses, including platelet function testing * Perform oral glucose tolerance tests (OGTT) to assess insulin resistance * Undergo echocardiography, cardiac magnetic resonance imaging, and cardiac scintigraphy to evaluate heart structure, function, and perfusion * Attend follow-up visits at 1, 3, 6, and 12 months Open-label extension: After the 12-month randomized phase, participants originally assigned to usual care will be offered open-label vericiguat and followed for an additional 12 months. This exploratory extension will reassess study outcomes to evaluate the consistency and magnitude of response to vericiguat in the prior control cohort.

Inclusion Criteria: * Written informed consent from an adult patient (≥ 18 years old) to participate in the clinical study, * Stable HFrEF defined as no heart failure worsening in the 6 months before randomization that required hospitalization or outpatient diuretic treatment, * Confirmed diagnosis of chronic heart failure with reduced ejection fraction (LVEF \< 50%, confirmed by echocardiography) within 12 months before randomization, * Stable GDMT for HFrEF for at least 3 months prior to randomisation. Exclusion Criteria: * Systolic blood pressure \< 100 mmHg or symptomatic hypotension, * Current or planned use of long-acting nitrates, soluble guanylate cyclase stimulators, or phosphodiesterase type V inhibitors, * Known allergy/hypersensitivity to soluble guanylate cyclase stimulators, * Awaiting heart transplantation or dependence on continuous inotropic therapy * Cardiac amyloidosis, sarcoidosis, myocarditis, stress cardiomyopathy, or tachycardic cardiomyopathy, * Acute coronary syndrome, coronary artery bypass grafting, or percutaneous coronary intervention in the past three months before randomisation, * Long-term mechanical circulatory support of the left ventricle, * Active infection, * Chronic kidney disease stage 4 or 5, and * Advanced liver failure classified as Child-Pugh B or C.