We recommend that hemodynamically stable patients with AF/AFL of known duration &lt;48 hours for whom a strategy of rhythm control has been selected may generally undergo cardioversion without prior or subsequent anticoagulation. However, if the patient is at particularly high risk of stroke (eg, mechanical valve, rheumatic heart disease, recent stroke, or transient ischemic attack), cardioversion should be delayed and the patient should receive OAC for 3 weeks before and at least 4 weeks post-cardioversion.<br /><br /><b>Following attempted cardioversion:</b> If AF or AFL persists, recurs, or if symptoms suggest that the presenting AF/AFL has been recurrent, antithrombotic therapy (OAC or aspirin as appropriate) should be commenced and continued indefinitely.<br/><br/>If NSR is achieved, the need for ongoing antithrombotic therapy should be determined based on the risk of stroke according to CHADS<sub>2</sub> score and early consultant follow-up should be arranged. (Recommendation Strong, Quality Moderate)<br /><br /><b>Values and preferences: </b> These recommendations place a high value on minimizing stroke risk by appropriate anticoagulation prior to cardioversion in all patients except those at very low risk of stroke due to a short duration of AF/AFL. A lower value is placed on symptomatic improvement associated with immediate cardioversion in patients who are deemed not to be at very low risk of stroke despite an apparent short duration of AF/AFL.