Conduction system pacing as a primary strategy for cardiac resynchronization therapy in reduced ejection fraction: An updated systematic review and meta-analysis of randomized controlled trialswe.

BACKGROUND: Biventricular pacing (BVP) is the standard for cardiac resynchronization therapy (CRT), particularly in left bundle branch block (LBBB). However, conduction system pacing (CSP) may offer superior outcomes as a physiological alternative. We evaluated the clinical efficacy of CSP compared with BVP as a primary strategy for patients with heart failure indicated for CRT. METHODS: A systematic review and meta-analysis was conducted using MEDLINE and the Cochrane Library databases. We included randomized controlled trials (RCTs) comparing CSP with BVP in patients with heart failure and a left ventricular ejection fraction below 50%. Pooled estimates were determined using a random-effects model for all outcomes. RESULTS: Twelve RCTs involving 1223 patients were included. CSP significantly improved the echocardiographic response compared with BVP in the overall cohort (odds ratio [OR]: 1.73; 95% confidence interval [CI]: 1.19-2.52) and the LBBB subgroup (OR: 1.74; 95% CI: 1.15-2.62). CSP revealed significant improvements in NYHA functional class (standardized mean difference: -0.27; 95% CI: -0.46 to -0.08) and 6-min walk distance (mean difference: 21.6 m; 95% CI: 8.07 to 35.14). While composite endpoints (OR: 0.59; 95% CI: 0.33 to 1.08) and mortality (OR: 0.90; 95% CI: 0.39 to 2.11) showed trends favoring CSP, neither reached statistical significance. There was no significant difference in procedural crossovers between the groups (OR: 1.24; 95% CI: 0.54 to 2.87). CONCLUSION: Compared with BVP, CSP improved echocardiographic and functional response in patients requiring CRT. CSP as a primary strategy may be considered in selected patients, but large RCTs with hard clinical endpoints are needed.