Impact of Preexisting Left Bundle Branch Block in Transcatheter Aortic Valve Replacement Recipients

Background: The impact of preexisting left bundle branch block (LBBB) in transcatheter aortic valve replacement (TAVR) recipients is unknown. The aim of this study was to determine the impact of preexisting LBBB on clinical outcomes after TAVR. Methods and Results: This multicenter study evaluated 3404 TAVR candidates according to the presence or absence of LBBB on baseline ECG. TAVR complications and causes of death were defined according to Valve Academic Research Consortium-2 definitions. Follow-up outpatient visits or telephone interviews were conducted at 30 days, 12 months, and yearly thereafter. Echocardiography examinations were performed at baseline, at hospital discharge, and at 1-year follow-up. Preexisting LBBB was present in 398 patients (11.7%) and was associated with an increased risk of permanent pacemaker implantation (PPI; 21.1% versus 14.8%; adjusted odds ratio, 1.51; 95% CI, 1.12–2.04) but not death (7.3% versus 5.5%; adjusted odds ratio, 1.33; 95% CI, 0.84–2.12) at 30 days. At a mean follow-up of 22±21 months, there were no differences between patients with and without preexisting LBBB in overall mortality (adjusted hazard ratio, 0.94; 95% CI, 0.75–1.18) and cardiovascular mortality (adjusted hazard ratio, 0.90; 95% CI, 0.68–1.21). In a subanalysis of 2421 patients without PPI at 30 days and with complete follow-up about the PPI, preexisting LBBB was not associated with an increased risk of PPI or sudden cardiac death. Patients with preexisting LBBB had a lower left ventricular ejection fraction (LVEF) at baseline and at 1-year follow-up ( P <0.001 for both), but those with low LVEF exhibited a similar increase in LVEF over time after TAVR compared with patients with no preexisting LBBB ( P =0.327). Conclusions: Preexisting LBBB significantly increased the risk of early (but not late) PPI after TAVR, without any significant effect on overall mortality or cardiovascular mortality. Preexisting LBBB was associated with lower LVEF pre-TAVR but did not prevent an increase in LVEF post-TAVR similar to patients without LBBB.