Tranilast Prevents Atrial Remodeling and Development of Atrial Fibrillation in a Canine Model of Atrial Tachycardia and Left Ventricular Dysfunction

Objectives This study sought to assess the effects of tranilast on atrial remodeling in a canine atrial fibrillation (AF) model. Background Tranilast inhibits transforming growth factor (TGF)-β1 and prevents fibrosis in many pathophysiological settings. However, the effects of tranilast on atrial remodeling remain unclear. Methods Beagles were subjected to atrial tachypacing (400 beats/min) for 4 weeks while treated with placebo (control dogs, n = 8) or tranilast (tranilast dogs, n = 10). Sham dogs (n = 6) did not receive atrial tachypacing. Atrioventricular conduction was preserved. Ventricular dysfunction developed in the control and tranilast dogs due to rapid ventricular responses. Results Atrial fibrillation duration (211 ± 57 s) increased, and AF cycle length and atrial effective refractory period shortened in controls, but these changes were suppressed in tranilast dogs (AF duration, 18 ± 10 s, p Conclusions Tranilast prevented atrial remodeling and suppressed AF development in a canine model. Its inhibition of TGF-β1 and Rac1 overexpression may contribute to its antiremodeling effects.