Pacemaker Implantation in Patients With Syncope, Bundle Branch Block and Negative Electrophysiological Study

INTRODUCTION: The long‑term need for permanent pacemaker (PM) implantation in patients with syncope, bundle branch block (BBB), and a negative electrophysiological study (EPS) is not well defined. METHODS AND RESULTS: We retrospectively analyzed consecutive patients undergoing EPS for syncope and any type of BBB between May 2012 and December 2023 at our Institution. Only individuals with a negative EPS and no pre‑existing indication for pacing were included. The primary endpoint was PM implantation during follow‑up. Eighty-nine patients with a negative EPS were included (median age 80 years; 63% male). An implantable loop recorder (ILR) was used in 57 patients (64%). At the time of EPS, 36 patients (40%) reported a single lifetime syncope, whereas 53 (60%) had multiple episodes (≥2). Over a median follow-up of 29.5 months, 33 patients (37%) underwent PM implantation, with cumulative rates of 28%, 32%, and 35% at 1, 2, and 3 years, respectively, reaching 46% at 7 years. On multivariate analysis, a history of multiple syncope (hazard ratio 2.39, 95% CI 1.03-5.53, p = 0.042) and ILR use (hazard ratio 2.44, 95% CI 1.04-5.73, p = 0.040) independently predicted PM implantation, while baseline conduction abnormalities and HV interval did not. CONCLUSION: Our findings highlighted the limited negative predictive value of EPS in patients with syncope and BBB. During extended follow-up, PM implantation is frequent and found to be associated with a clinical history of recurrent syncope and the use of ILR.