Importance:
Right bundle branch block (RBBB) is observed in approximately 5-14% of patients with heart failure (HF). Multiple observational studies have reported the association of RBBB with clinical outcomes in patients with HF. We performed a systematic review and meta-analysis to determine the prognostic significance of RBBB for patients with HF.
Data Sources:
We have systematically searched MEDLINE, EMBASE, Cochrane CENTRAL, Web of Science and Scopus through January 2014.
Study Selection:
Reviewers working independently and in duplicate screened all eligible abstracts that described all cause or cardiovascular mortality in patients with RBBB and HF. We excluded studies that reported unadjusted outcome, i.e.: unadjusted event rates.
Knowledge synthesis:
We pooled reported risk ratio and hazard ratio.
Main Outcomes:
All-cause mortality and cardiovascular mortality (death).
Results:
We found 12 relevant observational studies enrolling over 38,000 patients. Risk of bias was assessed using the Newcastle-Ottawa Scale. Included studies had at least a moderate quality. Seven of those evaluated prognosis of patients with RBBB and heart failure. After a mean follow up period of 2.5 years (range: 1-5 years), RBBB was associated with a statistically significant increased risk of all-cause mortality compared to patients with heart failure but no BBB, RR 1.27, 95% CI (1.08-1.50), Figure 1. The other 5 studies evaluated CHF patients receiving cardiac resynchronization therapy (CRT), comparing outcomes of patients with RBBB to those with LBBB. After a mean f/u period of 3 years, patients with RBBB were once again found to have an increased risk of all-cause mortality, RR 1.45, 95% CI 1.12-1.89.
Conclusion and Relevance:
RBBB in patients with HF is associated with higher all-cause mortality in comparison to patients without inter-ventricular conduction defects, as well as LBBB patients in patients undergoing CRT setting.
The risk of heart failure associated with the use of noninsulin blood glucose-lowering drugs: systematic review and meta-analysis of published observational studies
