For patients with AF of documented duration of 48 h or less undergoing elective cardioversion (electrical or pharmacologic), we suggest starting anticoagulation at presenta- tion (low-molecular-weight heparin or unfrac- tionated heparin at full venous thromboembolism treatment doses) and proceeding to cardiover- sion rather than delaying cardioversion for 3 weeks of therapeutic anticoagulation or a TEE-guided approach (Grade 2C). After suc- cessful cardioversion to sinus rhythm, we rec- ommend therapeutic anticoagulation for at least 4 weeks rather than no anticoagulation, regard- less of baseline stroke risk (Grade 2C). Decisions about long-term anticoagulation after cardio- version should be made in accordance with our risk-based recommendations for long-term anti- thrombotic therapy in section 2.1. 4.2 Patients Undergoing Urgent Cardioversion for Hemodynamically Unstable AF There are no published data regarding the opti- mal anticoagulation strategy to use before or dur- ing urgent cardioversion for patients with AF and hemodynamic instability. Initiation of anticoag- ulation immediately before urgent cardioversion (eg, with IV unfractionated heparin or low-molecular- weight heparin) would be expected to reduce the risk of stroke or thromboembolism based on studies that corresponds to plasma heparin levels of 0.3-0.7 International Units/mL antifactor Xa activity) should be started at the time of TEE and cardioversion per- formed within 24 h of the TEE if no thrombus is seen. A few observational studies and one RCT have suggested that low-molecular-weight heparin has similar ef cacy compared with heparin or warfarin for immediate anticoagulation before TEE.146-150 Out- patients undergoing a TEE-guided approach may be started on a VKA (INR 2.5; range, 2.0-3.0) and the TEE and subsequent cardioversion scheduled for 5 days later (if the INR is in therapeutic range at that time). 