Conduction disturbances after TAVR - a 1-year follow-up
Authors: Alves Pinto R , Proenca T , Martins Carvalho M , Torres S , Grilo PD , Resende CX , Amador AF , Calvao J , Costa C , Oliveira S , Pestana G , Lebreiro A , Silva JC , Adao L , Macedo F 
Published: May 2021

Abstract

Funding Acknowledgements
Type of funding sources: None.

Introduction
Transcatheter aortic valve replacement (TAVR) is an established procedure to treat patients (pts) with symptomatic severe aortic stenosis. Although conduction disturbances remain the most frequent complication, there is a lack of consensus on their management, which leads to significant differences in permanent pacemaker (PPM) implantation rates between centers.

Purpose
To evaluate new conduction disturbances and PPM implantation in pts undergoing TAVR, peri-procedure and up to 1 year.

Methods
We retrospectively analyzed all pts who underwent TAVR at a tertiary center from October 2014 to November 2019; pts with a previous PPM were excluded (n = 30). Clinical and ECG data were collected at presentation and up to 1 year after implantation, including systematic interrogation of implanted PPM.

Results
340 pts underwent TAVR (57% female, mean age 80 ± 8years). CoreValve Evolut R was the most used valve (41% of pts), followed by CoreValve Evolut Pro (21%) and Acurate Neo (13%). Of the 77% pts who were in sinus rhythm pre-TAVR, 79% had normal atrioventricular (AV) conduction and 20% 1st degree AV block (AVB); 60% had no intraventricular (IV) conduction disturbance, 9% left bundle branch block (LBBB), 7% right bundle branch block (RBBB) and 7% RBBB plus fascicular block.
After TAVR, 50.9% of pts exhibited new conduction disturbances. Regarding AV conduction, 12.4% of pts developed advanced AVB and 20% of pts without previous disturbances developed 1st degree AVB. Concerning IV conduction, the most frequent disturbance was de novo LBBB (n = 109, 32,2%) which resolved in 56% of cases after 6 months. Among pts with previous RBBB, 42% developed advanced AVB; the presence of previous RBBB was the major risk factor for advanced AVB [OR = 8.5 (95% CI 4.1-17.5; p &lt; 0.001)] and PPM implantation [OR = 5.2 (95% CI 2.7-10.0; p &lt; 0.001)], followed by previous 1st degree AVB [OR = 2.3 (95% CI 1.2-4.4; p = 0.016) for PPM implantation]; previous FA or LBBB were not associated with advanced AVB or PPM implantation.
Overall, 19% of pts implanted a PPM post-TAVR (n = 63). The main reason was advanced AVB (60%), followed by LBBB plus 1st degree AVB (22%), isolated LBBB (5%) and alternating bundle branch block (ABBB) (5%). At first PPM evaluation, pts with advanced AVB had a median percentage of ventricular pacing (VP) of 80% (52% had VP &gt;90% and 14% &lt;1%) and one year after-TAVR the median percentage of VP was 83%. Concerning pts with LBBB plus 1st degree AVB, median VP at first assessment was 4% (38% had &lt; 1% of VP). In pts with isolated LBBB or ABBB, median VP at first evaluation was 13% and 11%, respectively.

Conclusion
LBBB was the most frequent de novo conduction disturbance after TAVR, with more than half of the cases resolving in the first 6 months. RBBB, on the other hand, was the major risk factor for advanced AVB and PPM implantation. Advanced AVB was associated with a high percentage of VP at 1-year follow-up, unlike pts with milder degrees of conduction delay.