AIMS: To evaluate the effectiveness and safety of vericiguat in patients with heart failure and reduced ejection fraction (HFrEF) following recent decompensation in routine clinical practice in Spain. METHODS: VERISEC is a prospective, multicentre registry of 835 consecutive patients initiating vericiguat at 41 centres in Spain. Functional class, biochemical markers, ventricular function, and clinical events were analysed during a 1-year follow-up. RESULTS: Patients (age 71.3 years [SD: 11.2], 78.9% male) received highly optimized baseline therapy: 91.5% SGLT2i, 90.7% beta-blockers, 85.4% RAASi, and 79.8% MRAs. Quadruple therapy remained stable (61.7% baseline to 63.0% at 12 months; P = .526). At 1-year follow-up, significant improvements were observed. NT-proBNP decreased from 3532.0 (IQR: 1689.3-6974.5) to 2291.5 pg/ml (IQR: 1063.0-5076.3; P < .001) and LVEF increased from 30.3% (SD: 7.6) to 35.4% (SD: 11.1; P < .001). NYHA class improved, with class II patients increasing from 55.6% to 62.2% (P < .001). Mean HF decompensations requiring intravenous diuretics decreased from 1.34 (SD: 1.1) in the preceding year to 0.65 (SD: 1.3) during follow-up. Non-HF cardiovascular hospitalizations decreased from 0.98 (SD: 1.4) to 0.39 (SD: 1.0). Vericiguat was discontinued in 13.4% of patients, primarily due to symptomatic hypotension (49.4%). Higher baseline NT-proBNP (per 1000-pg/ml increase) independently predicted discontinuation (OR: 1.06; 95% CI: 1.03-1.08; P < .001). CONCLUSIONS: Vericiguat added to optimized quadruple therapy was associated with reverse remodelling, reduced NT-proBNP, improved functional class, and a numerical reduction in HF-related events in real-world HFrEF patients. These findings confirm the clinical utility and safety of vericiguat in routine practice.