Leadless Atrial Pacing at Bachmann's Bundle Guided by Electroanatomic Mapping and Intracardiac Ultrasound.

INTRODUCTION: Leadless pacemakers (LPs) offer advantages over transvenous systems, but atrial LPs currently target the right atrial appendage (RAA), risking atrial dyssynchrony. METHODS AND RESULTS: We report five patients in whom electroanatomic mapping and intracardiac ultrasound guided LP implantation into Bachmann's bundle (BB), a site shown to improve interatrial conduction and reduce atrial fibrillation risk. In four of five patients, BB fixation was successful with low pacing thresholds and short P-wave duration. One patient required conversion to RAA pacing due to high BB pacing thresholds. No intraprocedural complications occurred. CONCLUSIONS: This series demonstrates the feasibility of leadless BB pacing, though technical challenges warrant further study.