Timing of cardioversion	Anticoagulation
Early cardioversion* in patients with atrial fibrillation for less than 48 hours	Heparin during cardioversion period to achieve PTT of 1.5 to2.5 times the baseline value
Early cardioversion* in patients with atrial fibrillation for more than 48 hours or an unknown duration, but without documented atrial thrombi	Heparin during cardioversion period to achieve PTT of 1.5 to 2.5 times the baseline value
	Warfarin (Coumadin) for 4 weeks after cardioversion to achieve target INR of 2.5 (range: 2.0 to 3.0)
Elective cardioversion in patients with atrial fibrillation for more than 48 hours or an unknown duration	Warfarin for 3 weeks before and 4 weeks after cardioversion to achieve target INR of 2.5 (range: 2.0 to 3.0)