While there are several completed clinical trials that address treatment strategy in patients with symptomatic and recurrent AF, there are no randomized clinical trials that address treatment for first-detected AF. In usual care, these patients are started on an atrioventricular nodal blocking agent (beta-blocker or non-dihydropyridine calcium channel blocker) along with stroke prevention therapy. The investigators hypothesize that earlier administration of a well-tolerated antiarrhythmic drug proven to reduce hospitalization may result in improved cardiovascular outcomes and quality of life in patients first-detected AF.

The purpose of this study is to determine if treatment with dronedarone on top of usual care is superior to usual care alone for the prevention of cardiovascular hospitalization or death from any cause in patients hospitalized with first-detected AF. All patients will be treated with guideline-recommended stroke prevention therapy according to the CHA2DS2-VASc score. The treatment follow-up period will be 12 months. There will be two follow-up visits. Consistent with the pragmatic nature of the trial, the first follow-up will occur between 3 -9 months and the 2nd will occur at 12 months (with a window of +/- 30 days). Approximately 3000 patients will be enrolled and randomly assigned (1:1) to study intervention. The study intervention will be dronedarone 400 mg twice daily in addition to usual care versus usual care alone.