Is early cardioversion for atrial fibrillation safe in patients with spontaneous echocardiographic contrast?

The 2006 American Heart Association guidelines for management of patients with atrial fibrillation state "For patients with no identifiable thrombus in the left atrium (LA) or left atrial appendage (LAA), cardioversion (CV) is reasonable immediately after anticoagulation with unfractionated heparin. Thereafter, continuation of oral anticoagulation is reasonable for an anticoagulation period of at least 4 weeks". For patients with thrombus identified by transesophageal echocardiography, guidelines recommend therapeutic oral anticoagulation for 3 weeks prior to and 4 weeks after elective cardioversion. Patients with spontaneous echo contrast (SEC) identified by TEE have a high risk of thromboembolic events,1-8 however, the guidelines do not address whether patients with SEC without thrombus can be safely cardioverted. This paper reviews the literature describing the pathogenesis of SEC, how it is detected, and whether elective cardioversion is safe. On the basis of our review, we believe that the risk of cardioembolic stroke after cardioversion of a patient with SEC is low, regardless of anticoagulation. The safe conclusion is that patients with SEC on TEE should receive therapeutic anticoagulation prior to cardioversion if possible and early cardioversion is not contraindicated.