Daily Medical Update

Conduction defects

Sunday, July 26, 2026

🔬 Practice-Changing Findings
Evidence from RCTs and meta-analyses published in the last 12 months.

1. Clinical and electrical outcomes of conduction system pacing versus right ventricular pacing in atrioventricular block: a systematic review and meta-analysis.

BMC cardiovascular disorders (2026) - Systematic Review and Meta-analysis

Key Findings

  • CSP reduced all-cause mortality versus RVP (RR 0.50, p < 0.0001) and heart failure hospitalization (RR 0.39, p < 0.0001).
  • CSP improved LVEF by 2.60% (p < 0.0001), reduced LVEDD by 1.54 mm (p < 0.0001), and shortened paced QRS duration.

📋 Practice Implication: For AV block patients expected to require frequent ventricular pacing, CSP should be discussed as a physiologic default when operator expertise is available, while acknowledging the evidence base includes substantial observational data.

2. Conduction System Pacing Versus Right Ventricular Pacing in Atrioventricular Block: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Pacing and clinical electrophysiology : PACE (2026) - Systematic Review and Meta-analysis of RCTs

Key Findings

  • Across five RCTs, CSP improved LVEF versus RVP by 1.31% (95% CI 0.49 to 2.14; p < 0.01).
  • CSP narrowed paced QRS duration by 28.44 ms (95% CI -38.96 to -17.92; p < 0.01), with comparable device and lead-related complications (RR 1.35; p = 0.71).

📋 Practice Implication: RCT-only evidence supports CSP as an incremental upgrade over RVP for electrical synchrony, though procedural planning should account for longer implant times.

3. Clinical outcomes of conduction system pacing versus right ventricular pacing in patients with atrioventricular block: a systematic review and meta-analysis of randomised controlled trials.

Open heart (2026) - Systematic Review and Meta-analysis of RCTs

Key Findings

  • CSP improved the composite clinical endpoint versus RVP (HR 0.54; 95% CI 0.31 to 0.95; p = 0.03).
  • Heart failure hospitalization was markedly reduced with CSP (RR 0.30; 95% CI 0.17 to 0.54; p < 0.0001), while all-cause mortality was not significantly different (RR 0.69; p = 0.25).

📋 Practice Implication: When counseling AV block patients, CSP's strongest randomized signal is prevention of heart failure morbidity rather than proven mortality benefit.

4. Comparative effects of biventricular and right ventricular pacing on clinical outcomes in atrioventricular block: a systematic review and meta-analysis.

BMC cardiovascular disorders (2026) - Systematic Review and Meta-analysis

Key Findings

  • BiV pacing reduced heart failure hospitalization versus RV pacing (RR 0.83; 95% CI 0.69 to 0.98; p = 0.03).
  • BiV pacing better preserved LVEF by 6.17% (95% CI 3.85 to 8.49; p < 0.00001), with no significant all-cause mortality reduction (RR 0.87; p = 0.21).

📋 Practice Implication: For AV block with high expected pacing burden, BiV pacing remains a reasonable individualized alternative when CSP is unsuitable or unavailable, particularly to preserve systolic function.

5. In the Search of Noninvasive Methods Delineating Left Bundle Branch Block Amendable With Conduction System Pacing.

Pacing and clinical electrophysiology : PACE (2026) - Retrospective Analysis

Key Findings

  • Patients with proximal LBBB had greater relative QRS shortening after CSP than those with distal disease (26% vs 14%; p < 0.02).
  • Proximal LBBB patients had larger reductions in LV end-systolic volume (41.3% vs 15.8%; p = 0.004) and greater ejection fraction improvement (17.1% vs 5.5%; p = 0.02).

📋 Practice Implication: High-resolution ECG-derived depolarization patterns may help identify LBBB patients most likely to respond to CSP-based CRT before committing to the pacing strategy.

💡 Summary

Recent AV block pacing evidence consistently favors conduction system pacing over right ventricular pacing for ventricular synchrony, LVEF preservation, and fewer heart failure events, although mortality benefit is less certain in randomized-only analyses. Biventricular pacing also reduced heart failure hospitalization and preserved systolic function versus RV pacing, while high-resolution ECG patterns may help identify LBBB patients most likely to respond to CSP-based CRT.

Generated from 120 PubMed abstracts · RCTs and Meta-analyses only

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