Objectives Atrial fibrillation (AF) is associated with significant morbidity and mortality.Substantial evidence suggests that the renin angiotensin system (RAS) has a role in the pathogenesis of AF.Angiotensin-converting enzyme 2 (ACE2), a monocarboxypeptidase capable of metabolising angiotensin Ⅱ (Ang Ⅱ) into angiotensin-(1-7) [Ang-(1-7)], has emerged as a potential therapeutic target.