TGFB1 and atrial fibrillation: TGFβ1, as an important mediator of atrial fibrosis and AF, is one of the major downstream mediators of Ang II and has been fully elucidated in multiple diseases including heart failure, myocardial infarction, and hypertension, etc., in humans and in animals (Everett and Olgin, 2007; Corradi et al., 2008).