Clinical Impact of Baseline Right Bundle Branch Block in Patients Undergoing Transcatheter Aortic Valve Replacement

Objectives This study sought to assess the influence of baseline right bundle branch block (RBBB) on all-cause and cardiovascular mortality as well as sudden cardiac death (SCD) among patients undergoing transcatheter aortic valve replacement (TAVR). Background Few data exist regarding the late clinical impact of pre-existing RBBB in TAVR recipients. Methods A total of 3,527 patients (mean age 82 ± 8 years, 50.1% men) were evaluated according to the presence of RBBB on baseline electrocardiography. Intraventricular conduction abnormalities were classified according to the American Heart Association, American College of Cardiology Foundation, and Heart Rhythm Society recommendations for standardization and interpretation of the electrocardiogram. TAVR complications and causes of death were defined according to Valve Academic Research Consortium 2 definitions. Results RBBB was present on baseline electrocardiography in 362 patients (10.3%) and associated with higher 30-day rates of permanent pacemaker implantation (PPI) (40.1% vs. 13.5%; p < 0.001) and death (10.2% vs. 6.9%; p = 0.024). At a mean follow-up of 20 ± 18 months, pre-existing RBBB was independently associated with all-cause mortality (hazard ratio [HR]: 1.31; 95% confidence interval [CI]: 1.06 to 1.63; p = 0.014) and cardiovascular mortality (HR: 1.45; 95% CI: 1.11 to 1.89; p = 0.006) but not with SCD (HR: 0.71; 95% CI: 0.22 to 2.32; p = 0.57). Patients with pre-existing RBBB and without PPI at discharge from the index hospitalization had the highest 2-year risk for cardiovascular death (27.8%; 95% CI: 20.9% to 36.1%; log-rank p = 0.007). In a subanalysis of 1,245 patients without PPI at discharge from the index hospitalization and with complete follow-up regarding the need for PPI, pre-existing RBBB was independently associated with the composite of SCD and PPI (HR: 2.68; 95% CI: 1.16 to 6.17; p = 0.023). Conclusions Pre-existing RBBB was found in 10% of TAVR recipients and was associated with poorer clinical outcomes. Patients with baseline RBBB without permanent pacemakers at hospital discharge may be at especially high risk for high-degree atrioventricular block and/or SCD during follow-up. Future studies should evaluate strategies aimed at the early detection of patients at risk for late development of high-degree atrioventricular block.