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

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.

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.

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.