TCT-536 Impact of Transcatheter Aortic Valve Replacement on His-Ventricular Interval

Abstract

Background High-grade atrioventricular block (HAVB) is a common complication of transcatheter aortic valve replacement (TAVR). Presence of right bundle branch block (RBB), higher mean aortic valve gradients, and post-dilatation of the prosthesis have been shown to predict HAVB following TAVR. In general, a prolongation of the His-ventricular interval (HVi) ≥70 ms is associated with higher progression rate to HAVB in patients with bundle branch block.

Methods Consecutive patients undergoing TAVR with a self-expanding valve (Medtronic CoreValve Evolut R) without pre-existing pacemaker devices were included from August 2017 to February 2019 at a single tertiary center. During the TAVR procedure, an electrophysiological study including measurements of HVi before (preHVi) and after (postHVi) valve implantation was performed. Electrocardiograms before TAVR, before discharge, and after 30 days were analyzed regarding new-onset left bundle branch block (LBB). HAVB was categorized as immediate HAVB (<48 h post procedure) and short-term HAVB (>48 h up to 30 days after TAVR).

Results Among the 112 TAVR patients (age 79.7 ± 6.9 years, 56% male, LVEF 52 ± 11%, 14% with pre-existing LBB), preHVi was 49.4 ± 9.7 ms, of which 5 (4%) patients had an HV interval ≥70 ms (80% LBB). After TAVR, a new-onset persistent LBB was documented in 38 (34%) patients and a transient LBB in 15 (13%). TAVR led to a significant average prolongation of HVi by 23% (to 59.8 ± 18.4 ms; p < 0.001), which increased the number of patients with HV interval >70 ms by 15 (13%) patients. Post-dilatation of the prosthesis (n = 15) was associated with a significant longer post-HV interval (72.3 ± 27.6 ms vs. 58.4 ± 16.3 ms; p = 0.007). An immediate HAVB after TAVR was observed in 6 (5%) patients, and a short-term HAVB in 4 (4%) patients. Pre-implantation HV interval was not predictive of immediate or short-term HAVB onset (p = 0.5). Post HVi was not associated with documentation of immediate or short-term HAVB after TAVI.

Conclusion TAVR leads to a significant prolongation of the HVi, particularly after post-dilatation. Neither pre- nor post-TAVR HVi were associated with immediate or short-term risk of HAVB, which might indicate a higher risk for progression rate to HAVB during long-term follow-up.