Lower interventricular septal thickness from computed tomography predicts the need for pacemaker implantation after TAVR

Background: Transcatheter aortic valve replacement (TAVR) is the standard treatment for severe aortic stenosis (AS) in select patients. While membranous septum length and pre-TAVR conduction disturbances are known predictors of permanent pacemaker implantation (PPI), the impact of muscular interventricular septal (IVS) thickness, assessed via pre-procedural computed tomography (CT), remains unclear. Objectives: The aim of the study was to evaluate the role of septal thickness with cardiac CT in predicting the need for PPI after TAVR. Methods: This retrospective cohort study analyzed patients undergoing TAVR between January 2019 and December 2022. IVS thickness was measured in end-systole at various levels below the membranous septum on pre-procedural CT scans. Multivariable logistic regression models assessed predictors of PPI, including IVS thickness. Results: Among the 338 patients (median age: 81 years; 42.6 % women), 20.1 % required PPI post-TAVR. Patients needing PPI had significantly lower IVS thickness 2 mm (3.9 ± 0.8 mm vs. 4.5 ± 1.3 mm, p < 0.001), 5 mm (5.9 ± 1.1 mm vs. 6.8 ± 1.8 mm, p < 0.001), and 10 mm (9.3 ± 1.1 mm vs. 10.6 ± 2.3 mm, p < 0.001) below the membranous septum. Multivariable analysis identified IVS thickness at 10 mm (HR: 0.73, 95 % CI: 0.56–0.96, p = 0.023), membranous septum length (HR: 0.79, 95 % CI: 0.67–0.94, p = 0.007), and right bundle branch block (HR: 7.70, 95 % CI: 3.70–15.90, p < 0.001) as independent predictors of PPI. Conclusions: IVS thickness on pre-procedural CT independently predicts PPI post-TAVR and improves risk stratification.