Soliman, Esraa

Background: The growing epidemiologic burden of heart failure (HF) poses a significant public health challenge. The development of conduction abnormalities influences HF outcomes, with left bundle branch block (LBBB) established as an independent mortality predictor. However, the impact of right bundle branch block (RBBB) on HF mortality is still controversial. The aim of this study is to compare survival in HF patients with and without RBBB. Methods: A comprehensive search was conducted on PubMed, Scopus, Web of Science, and Cochrane Library from inception to 12 October 2024. Raw data coordinates were extracted from Kaplan–Meier curves and merged into one dataset to reconstruct individual patient data. Hazard ratios (HR) with 95% confidence intervals (CI) were estimated using the Cox regression model. Dichotomous outcomes were pooled as risk ratios (RR) with 95% confidence interval (CI) using a random-effects model. Results: 13 studies incorporating 25714 HF patients were included in our analysis. Patients with RBBB had a significantly lower median survival of 41.0 months (95% CI: 39.0 – 44.8) compared to 51.2 months (95% CI: 49.2 – 52.8) in patients without RBBB. Survival at 1,3, and 5 years in RBBB patients was 74.2%, 54.0%, and 39.4%, respectively, compared to 77.2%, 58.1%, and 45.4% in patients without RBBB. The HR for mortality was 0.87 (95% CI: 0.83 – 0.91, p < 0.001), indicating a 13% lower risk of death in patients without RBBB compared to those with RBBB. There was no significant difference in cardiovascular mortality between groups (RR: 1.34; 95% CI: 0.88 – 2.05; p = 0.17). Conclusion: RBBB was associated with an increased risk of mortality in HF patients. These findings support the use of RBBB as a potential marker for risk stratification in HF. Further research with stricter inclusion criteria is warranted to better understand how the observed association is influenced by preserved versus reduced ejection fraction.

ABSTRACT Background Right bundle branch block (RBBB) has a high prevalence among heart transplant recipients and could influence outcomes. Crucially, the predictors of RBBB development after heart transplantation are not well‐established. Our study aims to evaluate the preoperative predictors and outcomes of RBBB following heart transplantation. Methods PubMed, Scopus, Web of Science, and Cochrane Library were searched up to November 15, 2024, to identify studies comparing heart transplant recipients with RBBB and without RBBB. Random‐effects models were used to estimate the pooled mean difference (MD) and risk ratios (RRs) with 95% confidence intervals (95% CIs). Results Nine studies incorporating 1507 patients were included. Patients who developed RBBB had higher graft ischemia time [MD: 10.0; 95% CI: 2.00–17.91; p = 0.01] and pulmonary vascular resistance (PVR) (MD: 0.44; 95% CI: 0.21–0.68; p < 0.001). There was no significant difference between RBBB and non‐RBBB patients in terms of pulmonary artery pressure (MD: 1.83; 95% CI: ‐0.86–4.53; p = 0.18) or donor age (MD: 1.51; 95% CI: ‐0.30– 3.31; p = 0.10). There was no significant difference in the prognosis of RBBB patients in terms of acute rejection (RR: 1.06; 95% CI: 0.70–1.61; p = 0.78), chronic rejection (RR: 0.92; 95% CI: 0.60–1.41; p = 0.70), or mortality (RR: 1.87; 95% CI: 0.81–4.31; p = 0.14). Conclusion Despite the association of RBBB with graft ischemia time and PVR, post‐transplant RBBB had no significant impact on mortality or graft rejection. Further research focusing on the identification period and applied definition of RBBB is recommended.