A single-centre cohort and short-term follow-up of patients who developed persistent new onset left bundle branch block after transcatheter aortic valve replacement

Background: The most common conduction abnormality after transcatheter aortic valve replacement (TAVR) is new-onset left bundle branch block (LBBB) with an exact frequency that varies based on the valve system used for TAVR. PPM implantation in patients with persistent new onset LBBB post TAVR is controversial. The primary objective of this study is to report PPM utilisation and mortality in this patient population. Methods: A TAVR registry included patients older than 18 years who underwent TAVR between March 2012 and June 2015 at University of Minnesota Medical Centre. After exclusion, 151 patients were divided into two groups; patients with persistent new onset LBBB after TAVR (new LBBB, n = 47) and patients without persistent new onset LBBB (no new LBBB, n = 104). Results: Among the 151 patients, 47 (31.1%) patients developed new-onset LBBB after the procedure and persisted at discharge. Left ventricular ejection fraction (LVEF) (52.5 +/- 11.1 vs. 56.4 +/- 10.8, p: .047) and mean aortic valve gradient (40.6 +/- 11.5 vs. 45.7 +/- 14.1, p: .022) were significantly higher in no new LBBB group. Among those with new LBBB, there was a significantly higher rate of PPM implant during index hospitalisation (14.9%, vs. 0%, p < .001). LVEF remained significantly lower at 1 year follow up in new LBBB group compared to no new LBBB group (51.8 +/- 11.2 vs. 57.6 +/- 8.3, p: .002). Also in new LBBB group, there was a non-significantly higher rate of all-cause mortality in 1 year compared to no new LBBB group (14.9% vs. 9.6% p: .34). There were no significant differences between patients with and without new LBBB with respect to PPM implant after discharge in 1 year (2.13% vs. 3.8% p: .58), length of stay (7.3 +/- 7.3 vs. 5.9 +/- 2.7 p: .09), post-op atrial fibrillation (AF) (16.3% vs. 8.5% p: .20). Conclusions: New onset LBBB was frequent conduction problem post TAVR and one-third of patients with new onset LBBB persisted at discharge. New LBBB after TAVR was associated with a higher risk of PPM implantation during the index hospitalisation but not after discharge. Our findings suggest that early PPM implantation for post-TAVR LBBB is not indicated without complete or high degree AV block. Further research is required to identify the patients with new LBBB who would progress to advanced AV block or heart failure.