The Transcatheter Aortic Valve Replacement-Conduction Study: The Value of the His-Ventricular Interval in Risk Stratification for Post-TAVR Atrioventricular-Block.

Background: There is no clear consensus regarding the optimal risk stratification of high-degree atrioventricular block (HDAVB) after transcatheter aortic valve replacement (TAVR). Methods: This prospective study sought to determine the utility of the pre- and post-TAVR His-ventricular (HV) interval in the risk stratification of post-TAVR HDAVB. One hundred twenty-one patients underwent an electrophysiology study before and after TAVR. The primary outcome was HDAVB requiring pacemaker implantation within 30 days post-TAVR. A separate retrospective cohort was analyzed to determine the postoperative interval at which the risk of HDAVB is reduced to <5%. Results: HDAVB occurred in 12 (10%) patients. Baseline right bundle branch block (RBBB) (odds ratio [OR]: 13.6), implant depth >4 mm (OR: 3.9), use of mechanically- or self-expanding valves (OR: 6.3), and post-TAVR HV > 65 ​ms (OR: 4.9) were associated with increased risk of HDAVB, whereas PR intervals and pre-TAVR HV were not. In patients without baseline RBBB or new persistent left bundle branch block (LBBB), not one patient with post-TAVR HV < 65 ​ms developed HDAVB. In the separate retrospective cohort (N = 1049), the risk of HDAVB is reduced (<5%) on postoperative days 4 and 3 in patients with pre-TAVR RBBB and post-TAVR persistent LBBB, respectively. Conclusions: Baseline RBBB, new persistent LBBB, implant depth >4 mm, and a post-TAVR HV ≥ 65 ​ms were associated with a higher risk of post-TAVR HDAVB, whereas an HV ≤ 65 ​ms was associated with a lower risk. The pre-TAVR HV was not associated with our outcome, and the delta HV did not have practical incremental prognostic value. Among those without pre-TAVR RBBB or post-TAVR persistent LBBB, no patients with post-TAVR HV < 65 ​ms developed HDAVB.