Angiotensin II-Antagonist in Paroxysmal Atrial Fibrillation (ANTIPAF)-Trial

Study Questions:

Does olmesartan, an angiotensin-receptor blocker (ARB), prevent paroxysmal atrial fibrillation (AF)?


In this randomized, double-blind, multicenter trial, 425 patients (mean age 62 years) with paroxysmal AF and without structural heart disease were randomly assigned to treatment with olmesartan, 40 mg/day (n = 214), or placebo (n = 211). Treatment with rhythm-control antiarrhythmic agents was not allowed. Transtelephonic monitoring was performed at least once daily for 1 minute during a follow-up of 12 months. The primary endpoint was the AF burden, defined as the percentage of days with AF divided by the total number of days with transtelephonic recordings.


A mean of 207 transtelephonic recordings per patient were available for review. There was no significant difference in the AF burden between the olmesartan group (15.1%) and the placebo group (14.7%). There also was not a significant difference in the percentage of patients in whom AF progressed from paroxysmal to persistent between the olmesartan (9.2%) and placebo (9.0%) groups.


The authors concluded that treatment with an ARB does not reduce the burden of idiopathic paroxysmal AF.


Meta-analyses have indicated that ARBs and angiotensin-converting enzyme inhibitors do prevent AF, but this effect in large part has been limited to patients with structural heart disease and/or patients also treated with a traditional rhythm-control agent such as amiodarone. The present study provides strong evidence that ARBs on their own have no therapeutic effects in patients with idiopathic AF. It is possible that the beneficial effects of ARBs at least in part are due to modulation of atrial remodeling. Atrial remodeling is unlikely to play a significant role in the pathogenesis of idiopathic paroxysmal AF, perhaps explaining why this was a negative study.

Keywords: Angiotensin Receptor Antagonists

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