Several observational studies indicate that approximately one-half of patients will have recurrence of AF at 1 year after cardioversion.152-156 The AFFIRM study, in which many patients stopped anticoagulation after initial (apparently) successful restoration of sinus rhythm, found similar rates of thromboembolism with a rhythm control strategy compared with a rate con- trol strategy.125 Finally, patients with PAF often are asymptomatic during episodes of AF recurrence, with one series suggesting that only one in every 12 paroxysms are symptomatic.157 These observations suggest that decisions about long-term antithrom- botic therapy should be primarily based on a patient s risk for stroke (see section 2.1) rather than on the prevailing rhythm at 4 weeks postcardioversion. Recommendation 4.1.1. For patients with AF of greater than 48 h or unknown duration undergoing elective electri- cal or pharmacologic cardioversion, we recom- mend therapeutic anticoagulation (adjusted-dose VKA therapy, target INR range 2.0-3.0, low- molecular-weight heparin at full venous throm- boembolism treatment doses, or dabigatran) for at least 3 weeks before cardioversion or a TEE- guided approach with abbreviated anticoagu- lation before cardioversion, rather than no anticoagulation (Grade 1B). We recommend therapeutic anticoagulation for at least 4 weeks after successful cardioversion to sinus rhythm, rather than no anticoagulation, regardless of the baseline risk of stroke (Grade 1B). 