Introduction:Right bundle branch block (RBBB) is an easily obtainable cardiac biomarker. Hence, we investigated its prognostic significance in patients with severe aortic regurgitation (AR).Hypothesis:RBBB on electrocardiography may serve to prognosticate clinical outcomes in patients with severe aortic regurgitation.Methods:This single-center observational study included 756 consecutive patients with severe AR screened through the echocardiographic database from 1993 to 2007. Detailed chart reviews were performed for clinical, echocardiographic, therapeutic and survival data. Mortality data were also obtained from the Social Security Death Index until the end of 2014. Survival was analyzed as a function of RBBB.Results:Of the 756 patients with severe AR, RBBB was present in 54 (7%) patients at initial assessment; mean age 60?18 years and 41% women. Over a follow-up of up to 22 years, there were 434 deaths. Presence of RBBB was associated with lower survival (figure, p=0.003). RBBB was associated with lower survival in both surgically and medically managed patients. Patients RBBB were older (67+16 vs 60+17 years, p=0.007), had lower LV ejection fraction (49+20 vs 54+18%, p=0.04), and greater amount of mitral (68% vs.44%, p=0.001) and tricuspid (48% vs.34%, p=0.03) regurgitation. RBBB, however, was not an independent predictor of survival after adjusting for these group differences by Cox regression analysis.Conclusions:Presence of RBBB in severe AR is a simple electrocardiographic marker of higher mortality and is associated with older age, lower LV ejection fraction and greater amounts of mitral and tricuspid regurgitation.