Research is also needed to inform recommendations about dif- ferent antithrombotic therapy regimens for patients with AF undergoing placement of an intracoronary artery stent or who experience an ACS (eg, triple therapy with oral anticoagulation, clopidogrel, and aspirin; dual antiplatelet therapy with clopidogrel and aspirin; or combination oral anticoagulation and aspirin or clopidogrel). Finally, all existing stroke risk strati cation and bleeding risk strati cation schema for patients with AF have modest predictive value, and development of more-accurate risk strati cation systems is needed to facilitate a more-accurate esti- mation of net clinical bene t for individual patients. of elective cardioversion. It is important to note that the initiation of anticoagulation therapy should not delay any emergency interventions to stabilize the patient. Recommendation 4.2. For patients with AF and hemodynamic instability undergoing urgent cardioversion (electrical or pharmacologic), we suggest that therapeutic-dose parenteral anticoagulation be started before cardioversion, if possible (Grade 2C), but that initiation of anticoagulation must not delay any emergency intervention (Grade 2C). After successful cardioversion to sinus rhythm, we suggest therapeutic anticoag- ulation for at least 4 weeks after successful car- dioversion to sinus rhythm rather than no anticoagulation, regardless of baseline stroke risk (Grade 2C). Decisions about anticoagulation beyond 4 weeks should be made in accordance with our risk-based recommendations for long- term antithrombotic therapy in section 2.1. 4.3 Patients Undergoing Elective or Urgent Cardioversion for Atrial Flutter There are no published data regarding the optimal anticoagulation strategy to use for patients under- going cardioversion for atrial utter. Although some observational studies suggest that the risk of throm- boembolism after cardioversion for atrial utter is low, even without anticoagulation, other studies have documented a similar risk of thromboembolism in patients after cardioversion for atrial utter and AF.140,162,163 This may be because AF and atrial utter often coexist. 