Objective:
Multiple large population based observational studies have evaluated the association of various ECG changes with long term adverse outcomes demonstrating conflicting results regarding the significance of right bundle branch block (RBBB). Therefore, we conducted a systematic review and meta-analysis to determine the prognostic significance of RBBB in healthy population.
Methods:
This systematic review follows an a priori established protocol and is reported following the PRISMA statement (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). We systematically searched EMBASE, Web of Science and Scopus through January 2014. We also consulted with content experts to recommend studies for screening. Reviewers working independently and in duplicate screened all eligible abstracts, selecting randomized trials and prospective cohort studies that described all cause mortality or cardiovascular death in patients with RBBB. We excluded studies that reported unadjusted outcome or unadjusted event rates. For statistical analysis, hazard ratios were considered to approximate risk ratios. The main outcomes of the study are all-cause mortality and cardiovascular mortality.
Results:
Based on the eligibility, four large cohorts, with total patient count > 100,000 were included in the meta-analysis. Risk of bias was assessed using the Newcastle-Ottawa scale and included studies were deemed to be of high quality. As demonstrated in Figure 1, RBBB was not associated increase in all-cause mortality (RR 1.05; 95% CI 0.89-1.25) or cardiovascular mortality (RR 1.09; 95% CI 0.70-1.69).
Conclusion:
In asymptomatic healthy patients, RBBB is not associated with poor outcome.
Diagnosis, prognostic significance, and characteristics of new-onset right bundle-branch block in patients with acute myocardial infarction: Protocol for a systematic review and meta-analysis