Prevention of Thromboembolism Recommendations for Prevention of Thromboembolism Referenced studies that support modified recommendations are summarized in Online Data Supplement 6. COR LOE Recommendations I B-R For patients with AF or atrial flutter of 48 hours duration or longer, or when the duration of AF is unknown, anticoagulation with warfarin (INR 2.0 to 3.0), a factor Xa inhibitor, or direct thrombin inhibitor is recommended for at least 3 weeks before and at least 4 weeks after cardioversion, regardless of the CHA2 -VASc score or the method (electrical or pharmacological) used to restore sinus rhythm.S6.1.1-1 S6.1.1-12 MODIFIED: The 2014 AF Guideline recommendation for use of warfarin around the time of cardioversion was combined with the 2014 AF Guideline recommendation for NOACs to create a single recommendation. This combined recommendation was updated to COR I/LOE B-R from COR IIa/LOE C for NOACs in the 2014 AF Guideline on the basis of additional trials that have evaluated the use of NOACs with cardioversion. I C For patients with AF or atrial flutter of more than 48 hours duration or unknown duration that requires immediate cardioversion for hemodynamic instability, anticoagulation should be initiated as soon as possible and continued for at least 4 weeks after cardioversion unless contraindicated. CLINICAL STATEMENTS AND GUIDELINES I C-EO After cardioversion for AF of any duration, the decision about long-term anticoagulation therapy should be based on the thromboembolic risk profile and bleeding risk profile. MODIFIED: The 2014 AF Guideline recommendation was strengthened with the addition of bleeding risk profile to the long- term anticoagulation decision-making process. 