The impact of pre-existing 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 pre-existing LBBB on clinical outcomes after TAVR.

This multicenter study evaluated 3404 TAVR candidates according to the presence or absence of LBBB on baseline electrocardiogram. 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.

Pre-existing LBBB was present in 398 patients (11.7%) and was associated with an increased risk of permanent pacemaker implantation (PPI) (21.1% vs. 14.8%; adjusted OR: 1.51, 95% CI: 1.12–2.04) but not death (7.3% vs. 5.5%; adjusted OR: 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 pre-existing LBBB in overall mortality (adjusted HR: 0.94, 95% CI: 0.75–1.18) and cardiovascular mortality (adjusted HR: 0.90, 95% CI: 0.68–1.21). In a sub-analysis of 2421 patients without PPI at 30 days and with complete follow-up regarding the PPI, pre-existing LBBB was not associated with an increased risk of PPI or sudden cardiac death. Patients with pre-existing LBBB had a lower 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 following TAVR compared to patients with no pre-existing LBBB (P=0.327) (Fig. 1).

Pre-existing LBBB significantly increased the risk of early (but not late) PPI after TAVR, without any significant effect on overall mortality or cardiovascular mortality. Pre-existing LBBB was associated with lower LVEF pre-TAVR, but did not prevent an increase in LVEF post-TAVR similar to patients without LBBB.