Left bundle branch block after transcatheter aortic valve replacement: comparison of two risk stratification strategies

Background Left bundle branch block (LBBB) remains the most frequent conduction disturbance after transcatheter aortic valve replacement (TAVR). Current ESC guidelines recommend two risk-stratification strategies with a class IIa indication: electrophysiological testing (EPS) or ambulatory ECG monitoring. These strategies have not yet been directly compared. Purpose To compare clinical outcomes and pacemaker (PM) implantation rates in patients with LBBB after TAVR, stratified using either EPS or 14-day ambulatory ECG-patch monitoring. Methods Adult patients undergoing TAVR at a Swiss tertiary centre were prospectively enrolled. Those with pre-existing or new-onset LBBB post-procedure underwent either EPS (Phase 1) or 14-day ECG-patch monitoring (Phase 2). Patients with prior PMs or immediate post-TAVR PM implantation were excluded. In Phase 1, PM implantation was guided by a prolonged His-ventricular (HV) interval the day after TAVR (>55 ms until 2022, thereafter >70 ms). In Phase 2, patients were discharged with ECG-patch monitoring and received PM therapy only if high-grade atrioventricular (AV) block was documented. The primary endpoint was a composite of syncope, fall, unplanned cardiovascular (CV) hospitalization, or all-cause death within 90 days post-TAVR. Results 296 patients undergoing TAVR developed new-onset or had pre-existing LBBB (median age 82 years, 46% female). Among these, 195 patients (65.9%) underwent EPS and 101 (34.1%) received ECG-patch monitoring. Within 90 days, 50 events (25.6%) occurred in the EPS group (28 CV hospitalizations, 15 syncope or falls, and 7 deaths) versus 24 events (23.8%) in the patch group (15 CV hospitalizations, 7 syncope or falls, and 2 deaths; p = 0.27). PM implantation within 30 days occurred in 46 patients (23.6%) of EPS patients versus 6 patients (5.9%) in the patch group (p < 0.001). Among EPS patients, 35 (17.9%) received a PM due to a prolonged HV interval, while in the ECG patch group 4 patients (4.0%) required PM implantation for AV block detected during monitoring (p < 0.001). Conclusion In patients with LBBB after TAVR, clinical event rates were comparable between EPS-guided and ECG-patch-based risk stratification. However, EPS guidance resulted in significantly higher pacemaker implantation rates. Ambulatory ECG monitoring may therefore represent a safe, less invasive alternative for post-TAVR LBBB management.