e534S Antithrombotic Therapy for Atrial Fibrillation (Grade 2C), but that initiation of anticoagulation must not delay any emergency intervention (Grade 2C). After successful cardioversion to sinus rhythm, we suggest therapeutic antico- agulation for at least 4 weeks after successful cardioversion to sinus rhythm rather than no anticoagulation, regardless of baseline stroke risk (Grade 2C). Decisions about anticoagulation beyond 4 weeks should be made in accordance with our risk-based recommendations for long- term antithrombotic therapy in section 2.1. 4.3. For patients with atrial utter undergo- ing elective or urgent pharmacologic or elec- trical cardioversion, we suggest that the same approach to thromboprophylaxis be used as for patients with atrial brillation undergoing cardioversion. Atrial brillation (AF) is the most common sus- tained cardiac arrhythmia. One in four individ- uals aged 40 years will develop AF during his or her lifetime, and it has been estimated that by the year 2050, up to 16 million Americans will have AF.1,2 Nonrheumatic AF is a strong, independent predictor of ischemic stroke associated with a vefold increase in risk.3 Without thromboprophylaxis, the risk of ischemic stroke in patients with nonrheumatic AF, as seen in the control arms of the original trials of antithrombotic therapy in AF, is 5% per year.4 Over the past 2 decades, considerable work has been done to evaluate antithrombotic therapies to prevent stroke in patients with AF, and the eld continues to evolve with the emergence of a new generation of oral anticoagulants. This article begins with a discussion of the methods used to develop our recommendations for antithrombotic therapy in patients with AF. Next, we provide our treatment recommendations, divided into the following sections: 1. Antithrombotic therapy in patients with AF in general (includes patients with permanent, per- sistent, or paroxysmal AF [PAF]) 2. 