Pre-existing left bundle branch block and clinical outcomes after transcatheter aortic valve replacement

BackgroundThere are currently few reports on pre-existing left bundle branch block (LBBB) in patients undergoing transcatheter aortic valve replacement (TAVR). Nor are there any studies comparing patients with new onset LBBB to those with pre-existing LBBB. This study aimed to investigate the association with pre-existing or new-onset LBBB and clinical outcomes after TAVR.MethodsUsing data from the Japanese multicenter registry, 5996 patients who underwent TAVR between October 2013 and December 2019 were included. Patients were classified into 3 groups: no LBBB, pre-existing LBBB and new onset LBBB. The 2-year clinical outcomes were compared between 3 groups using Cox proportinal hazard models and propensity score analysis to adjust the differences in baseline characteristics.ResultsOf 5996 patients who underwent TAVR, 280 patients (4.6%) had pre-existing LBBB and new onset LBBB occurred in 1658 patients (27.6%). Compared with no LBBB group, multivariable Cox regression analysis showed that pre-existing LBBB was associated with a higher 2-year all-cause (adjusted hazard ratio [aHR]: 1.39; 95% confidence interval [CI]: 1.06-1.82; p =0.015) and cardiovascular mortality (aHR: 1.62; 95% CI: 1.05-2.54; p =0.027), but also with higher all-cause (aHR:1.43, 95% CI:1.07-1.91; p =0.016) and cardiovascular mortality (aHR: 1.84, 95% CI: 1.14-2.98; p =0.012) than new onset LBBB group. Heart failure was the most common cause of cardiovascular death, with more heart failure deaths in the pre-existing LBBB group.ConclusionsPre-existing LBBB was independently associated with poor clinical outcomes reflecting increased risk of cardiovascular mortality after TAVR. Patients with pre-existing LBBB should be carefully monitored.What is Known?There are currently few reports on pre-existing left bundle branch block (LBBB) in patients undergoing transcatheter aortic valve replacement (TAVR). Nor are there any studies comparing patients with new onset LBBB to those with pre-existing LBBB.What the Study Add?Patients with pre-existing LBBB not only had a higher mortality than those without LBBB, but also had a worse prognosis than those with new onset LBBB.This was because patients with pre-existing LBBB had more heart failure deaths.Patients with pre-existing LBBB should be carefully monitored after TAVR. Further investigation will be required to corroborate our findings.