ABCB1 and atrial fibrillation: However, the role of genetics in its pharmacokinetics and outcomes remains unclear.<h4>Aim of study</h4>To explore the link between the ABCB1 (rs4148738 C>T) polymorphism, rivaroxaban steady-state plasma levels, and the occurrence of bleeding events in AF patients.Patients and methods: This cross-sectional study examines patients with AF treated with rivaroxaban anticoagulation from September 2024 to March 2025.