Warfarin plus aspirin was not given a recommendation in Author et al either as an alterna- tive or in preference to dual antiplatelet therapy for patients post-ACS because of pragmatic issues (physician reluctance, burden of use, etc). However, www.chestpubs.org CHEST / 141 / 2 / FEBRUARY, 2012 SUPPLEMENT e565S clinical trials, but because these patients often have concomitant AF or are at increased risk of devel- oping AF, it is reasonable to base decisions regard- ing antithrombotic therapy on the risk strati cation schemes used for AF (section 1.1). Recommendation 3.5. For patients with atrial utter, we suggest that antithrombotic therapy decisions follow the same risk-based recommendations as for AF. 4.0 Antithrombotic Therapy for Patients With AF Undergoing Cardioversion To minimize the risk of stroke and systemic embolism associated with cardioversion, therapeutic anticoagulation (eg, with adjusted-dose oral VKAs; INR 2.0-3.0) conventionally is recommended for a minimum of 3 weeks before, during, and for a min- imum of 4 weeks after the procedure. For some patients with AF of documented short duration (eg, 48 h), a common practice is to cardiovert with- out prolonged precardioversion anticoagulation. For patients with AF duration of .48 h or unknown duration, a TEE-guided approach is an alternative strategy that can simplify anticoagulation manage- ment before cardioversion. In this section, we sum- marize the evidence and give recommendations for the use of antithrombotic therapy in patients under- going electrical or pharmacologic cardioversion for AF (or atrial utter). 4.1 Patients Undergoing Elective Cardioversion of AF 4.1.1 Cardioversion of AF of More Than 48 h or Unknown Duration: Evidence favoring the ef cacy of pericardioversion anticoagulation is based on observational studies in mostly patients undergoing electrical rather than pharmacologic cardioversion. 