Q: ACE inhibitors or angiotensin receptor blockers (ARBs) have been used as an adjuvant treatment to prevent new onset and recurrent atrial fibrillation (AF). How these drugs directly help in the treatment of AF?
Answer: By preventing the formation of atrial fibrosis
Fibrosis in the atrial myocardium is one of a component of the substrate necessary for AF. Atrial fibrosis is stimulated by angiotensin-II. ACE inhibitors and angiotensin receptor blockers reduce the effect of angiotensin-II.
Reference: McEwan PE, Gray GA, Sherry L, et al. Differential effects of angiotensin II on cardiac cell proliferation and intramyocardial perivascular fibrosis in vivo. Circulation 1998; 98:2765.