Conduction System Pacing Versus Biventricular Cardiac Resynchronization in HFmrEF: A Systematic Review and...

To compare the efficacy and safety of conduction system pacing (CSP) versus biventricular pacing (BiVP) in patients with heart failure with mildly reduced ejection fraction (HFmrEF).

A systematic review and meta-analysis was conducted according to PRISMA guidelines. PubMed, Embase, and Cochrane databases were searched through August 2025. Studies enrolling patients with HFmrEF (left ventricular ejection fraction 41%-49%) who underwent CSP (His-bundle pacing [HBP] or left bundle branch pacing [LBBP]) or BiVP were included. Outcomes assessed included all-cause mortality, heart failure hospitalization (HFH), composite endpoints (death + HFH), echocardiographic and electrical remodeling, functional status, and procedural/device complications. Risk of bias was evaluated, and evidence was graded using the GRADE framework.

Seven studies (n = 1867 patients) met inclusion criteria. Pooled analysis showed CSP reduced HFH (HR 0.63, 95% CI 0.49-0.82) and improved the composite outcome of death or HFH (HR 0.64, 95% CI 0.43-0.94) compared with BiVP. Mortality was similar between groups (HR 0.82, 95% CI 0.63-1.07). CSP resulted in greater QRS narrowing (MD -14 ms) and consistent trends toward functional improvement. Device-related complications were numerically lower with CSP.

CSP, particularly LBBP, appears superior to BiVP in reducing HFH and enhancing electrical resynchronization in HFmrEF. Large randomized trials are warranted to confirm these findings and establish CSP as a standard resynchronization strategy.