MODIFIED: The 2014 AF Guideline recommendation was strengthened with the addition of bleeding risk profile to the long- term anticoagulation decision-making process. IIa B-NR For patients with AF or atrial flutter of less than 48 hours duration with a CHA2 - VASc score of 2 or greater in men and 3 or greater in women, administration of heparin, a factor Xa inhibitor, or a direct thrombin inhibitor is reasonable as soon as possible before cardioversion, followed by long-term MODIFIED: Recommendation COR was changed from I in the 2014 AF Guideline to IIa, and LOE was changed from C in the 2014 AF Guideline to B-NR. In addition, a specific -VASc score is now specified. IIa B For patients with AF or atrial flutter of 48 hours duration or longer or of unknown duration who have not been anticoagulated for the preceding 3 weeks, it is reasonable to perform transesophageal echocardiography before cardioversion and proceed with cardioversion if no left atrial thrombus is identified, including in the LAA, provided that anticoagulation is achieved before transesophageal echocardiography and maintained after cardioversion for at least 4 IIb B-NR For patients with AF or atrial flutter of less than 48 hours duration with a CHA2 - VASc score of 0 in men or 1 in women, administration of heparin, a factor Xa inhibitor, or a direct thrombin inhibitor, versus no anticoagulant therapy, may be considered before cardioversion, without the need for postcardioversion oral MODIFIED: Recommendation LOE was changed from C in the 2014 AF Guideline to B-NR to reflect evidence from 2 registry studies and to include specific CHA2 -VASc scores derived from study results. Recommendation-Specific Supportive Text (New or Modified) 1. 