Background: Vericiguat reduced the risk of cardiovascular death (CVD) or hospitalization for heart failure (HF) in patients with worsening HF and reduced left ventricular ejection fraction (LVEF).Objectives: The authors assessed the association of LVEF with biomarker levels, risk of outcome, and whether the effect of vericiguat was homogeneous across LVEF in the VICTORIA (Vericiguat Global Study in Subjects with Heart Failure With Reduced Ejection Fraction) trial.Methods: Patients were grouped by LVEF tertiles (≤24%, 25%-33%, and >33%). Patient characteristics, clinical outcomes, and efficacy and safety of vericiguat were examined by tertile. Prespecified biomarkers including N-terminal pro–B-type natriuretic peptide, cardiac troponin T, growth differentiation factor 15, interleukin 6, high-sensitivity C-reactive protein, and cystatin C were examined.Results: The mean LVEF was 29% ± 8% (range: 5%-45%). A pattern of higher N-terminal pro–B-type natriuretic peptide, high-sensitivity C-reactive protein, and interleukin 6 was evident in patients in the lowest LVEF tertile vs the other tertiles. Patients with lower LVEF experienced higher rates of the composite outcome (41.7%, 36.3%, and 33.4% for LVEF ≤24, 25-33, and >33; P < 0.001). There was no significant treatment effect heterogeneity of vericiguat across LVEF groups (adjusted HR from lowest to highest tertiles: 0.79 [95% CI: 0.68-0.94]; 0.95 [95% CI: 0.82-1.11]; 0.94 [95% CI: 0.79-1.11]; P for interaction = 0.222), although the HR was numerically lower in the lowest tertile. There was also no heterogeneity of effect for CVD and HF hospitalization individually (P interaction for CVD = 0.964; HF hospitalization = 0.438). Discontinuation of treatment because of adverse events, symptomatic hypotension, or syncope was consistent across the range of LVEF.Conclusions: Patients with lower LVEF had a distinctive biomarker profile and a higher risk for adverse clinical outcomes vs those with a higher LVEF. There was no significant interaction for the benefit of vericiguat across LVEF tertiles, although the largest signal for benefit in both the primary outcome and HF hospitalizations was noted in tertile 1 (LVEF ≤24%).</p