Abstract / Summary
Conduction system pacing (CSP) has emerged as a potential alternative to biventricular pacing (BiVP) for cardiac resynchronization therapy (CRT). However, the relative efficacy and safety of different CSP techniques remain unclear. We searched PubMed, Embase, Cochrane Library, and Web of Science for randomized controlled trials (RCTs) comparing CSP with BiVP. The primary outcome was the composite of all-cause death or heart failure hospitalization. Secondary outcomes included changes in left ventricular ejection fraction (LVEF) and left ventricular end-systolic volume (LVESV), echocardiographic response, QRS duration shortening, NYHA functional class improvement, and complication rate. Random-effects meta-analysis was used, with four pre-specified subgroups: CSP with optimization, strict left bundle branch pacing (LBBP), His-CRT, and left ventricular septal pacing (LVSP)-dominant. Nine RCTs (976 patients) were included. CSP showed no significant difference compared with BiVP for all-cause death or heart failure hospitalization (RR 0.70, 95% CI 0.36–1.36, P = 0.29, I 2 = 66%). Benefits varied by technique: strict LBBP provided the most consistent reverse remodeling (LVEF + 5.55%; LVESV − 23.98 mL) and hard-endpoint benefit (RR 0.29); His-CRT showed a similar but imprecise estimate derived from a single study; LVSP-dominant strategies showed no superiority. CSP also significantly improved NYHA class (MD − 0.20, P = 0.004) and shortened QRS duration (MD − 9.77 ms, P = 0.005), with no overall difference in complication rates. CSP showed no significant difference for all-cause death or heart failure hospitalization compared with BiVP, but significantly improved NYHA class and QRS duration. Subgroup analysis revealed marked heterogeneity: strict LBBP significantly reduced the composite endpoint and showed the most consistent LVEF and LVESV benefits; His-CRT showed a similar but imprecise estimate derived from a single study; LVSP-dominant strategies showed no superiority. These subgroup findings should be considered hypothesis‑generating. These findings support an individualized, technique-specific approach to CSP for CRT, but further direct comparative trials of LBBP versus other CSP techniques are needed to define its optimal role.