OBJECTIVES: We hypothesized that splanchnic nerve blockade (SNB) would attenuate increased exercise-induced cardiac filling pressures in patients with chronic HF. BACKGROUND: Chronic heart failure (HF) is characterized by limited exercise capacity driven in part by an excessive elevation of cardiac filling pressures. METHODS: This is a prospective, open-label, single-arm interventional study in chronic HF patients. Eligible patients had a wedge pressure ≥15 mm Hg at rest or ≥25 mm Hg with exercise on baseline right heart catheterization. Patients underwent cardiopulmonary exercise testing with invasive hemodynamic assessment, followed by percutaneous SNB with ropivacaine. RESULTS: Nineteen patients were enrolled, 15 of whom underwent SNB. The average age was 58 ± 13 years, 7 (47%) patients were women and 6 (40%) were black. Left ventricular ejection fraction was ≤35% in 14 (93%) patients. No procedural complications were encountered. SNB reduced mean pulmonary arterial pressure at peak exercise from 54.1 ± 14.4 (pre-SNB) to 45.8 ± 17.7 mm Hg (p < 0.001) (post-SNB). Similarly, SNB reduced exercise-induced wedge pressure from 34.8 ± 10.0 (pre-SNB) to 25.1 ± 10.7 mm Hg (p < 0.001) (post-SNB). The cardiac index changed with peak exercise from 3.4 ± 1.2 (pre-SNB) to 3.8 ± 1.1 l/min/m2 (p = 0.011) (post-SNB). After SNB, patients exercised for approximately the same duration at a greater workload (33 ± 24 W vs. 50 ± 30 W; p = 0.019) and peak oxygen consumption VO2 (9.1 ± 2.5 vs. 9.8 ± 2.7 ml/kg/min; p = 0.053). CONCLUSIONS: SNB reduced resting and exercise-induced pulmonary arterial and wedge pressure with favorable effects on cardiac output and exercise capacity. Continued efforts to investigate short- and long-term effects of SNB in chronic HF are warranted. Clinical Trials Registration (Abdominal Nerve Blockade in Chronic Heart Failure; NCT03453151).