Pacemaker risk stratification in patients with pre-existing right bundle branch block undergoing transcatheter aortic valve replacement.

Background: Patients with pre-existing right bundle branch block (RBBB) undergoing transcatheter aortic valve replacement (TAVR) face a high risk of permanent pacemaker implantation (PPI). However, additional predictors of PPI in this sub-population are unknown.

Methods: Retrospective multicenter study enrolling 530 patients with baseline RBBB without pacemaker undergoing TAVR in native aortic valve stenosis. The primary end-point was the incidence of PPI at 30-day and predictors of the primary end-point were used to determine PPI risk.

Results: PPI occurred in 229 (42.2%) patients at 30-day. Female gender (49.5% vs 39.9% in males, p=0.034), prolonged PR segment (61.1% if PR>240 ms vs 42.2% if PR <240 ms) and the use of self-expanding valves (51.9% vs. 36.2% in balloon-expandable, p=0.001) were associated with higher rates of PPI at 30-day. Other ECG parameters (QRS duration or left fascicular hemiblock) did not have relation with PPI. CT sub-analysis showed that valve to annulus oversizing >10% and a LVOT smaller than the annulus were significantly associated with PPI (p=0.026 and p=0.017, respectively). Multivariate analysis demonstrated that the best predictive model for PPI included female sex (OR 1.38, p=0.088), PR >240 ms (OR 2.62, p=0.008) and self-expanding valves (OR 1.95, p<0.001). The probability estimation for PPI ranged from 76.8% with all these factors present compared to 32.0% in the absence of them.

Conclusions: among patients with baseline RBBB undergoing TAVR, PPI was more frequent in females with PR>240 ms and treated with self-expanding valves. Appropriate risk stratification may help to detect low or high-risk individuals of PPI.