Is it safe to cardiovert atrial fibrillation without anticoagulation if the transoesophageal echocardiogram is normal?

The risk of thromboembolism after unprotected DC cardioversion for chronic atrial fibrillation is 5%. The use of transoesophageal echocardiographic guidance probably reduces this risk to around 1.3%. However, after conventional courses of anticoagulation, the risk is only 0.3 to 0.8%. Until there is further information from large randomised trials, the routine use of transoesophageal echocardiography cannot be recommended. However it should be considered in acute onset atrial fibrillation of less than 2 days duration in the presence of underlying structural heart disease or in individual patients who have previously suffered an embolic event.