Posterosuperior Bundle Pacing for Prevention of Atrial Fibrillation in Patients With Sinus Node Dysfunction

This study aims to evaluate whether posterosuperior bundle (PSB) pacing reduces the incidence of atrial fibrillation (AF) in patients with sinus node dysfunction (SND) undergoing pacemaker implantation. Approximately 300 patients will be enrolled and randomized to receive atrial pacing at either the PSB region or the right atrial appendage (RAA). The primary endpoint is the occurrence of AF episodes lasting ≥6 minutes, as detected by device or surface electrocardiogram. Patients will be followed for up to 24 months.

Inclusion Criteria: * Age ≥18 years * Indication for permanent pacemaker implantation, including: * Sinus node dysfunction, defined as at least one of the following: * Symptomatic sinus bradycardia * Tachy-brady syndrome * Chronotropic incompetence * Sinus pause / arrest * Atrioventricular block (if present); if ventricular pacing is required, left bundle branch area pacing is planned * Expected survival \>1 year * Panned implantation of a device capable of detecting atrial high-rate episodes * Willing and able to provide informed consent Exclusion Criteria: * Persistent atrial fibrillation (AF) (\>7 days), long-standing persistent AF, permanent AF, or prior atrioventricular node ablation * Prior cardiac implantable electronic device (CIED) requiring replacement, upgrade, or revision * Indication for cardioverter-defibrillator (ICD) or cardiac resynchronization therapy (CRT-D) * Prior cardiac surgery, severe hepatic or renal dysfunction, or other life-threatening systemic diseases * Acute myocardial infarction within 3 months before enrollment * Persistent left superior vena cava or dextrocardia * Pregnant or breastfeeding women, or women of childbearing potential not using effective contraception * Participation in another clinical trial that may interfere * Any condition that, in the opinion of the investigator, makes participation unsuitable