[Value and indications of transesophageal echocardiography before cardioversion of atrial fibrillation].

Transoesophageal echocardiography is essential for the diagnosis of left atrial thrombosis and its precursors (dense spontaneous contrast--reduced auricular emptying velocities) and for the diagnosis of complex aortic atheroma. The sensitivity and specificity of transoesophageal echocardiography for the diagnosis of left atrial thrombus are about 100% and about 90% for that of aortic atheroma. The formal indications for transoesophageal echocardiography before cardioversion are: atrial fibrillation complicated by stroke or a recent systemic embolism: atrial fibrillation complicated by mitral valve disease as the thrombo-embolic risk is major in this context: atrial fibrillation with a high thromboembolic risk: a history of stroke, presence of cardiac failure, diabetes, permanent hypertension, a very dilated left atrium (> or = 50 mm): apparently isolated atrial fibrillation for which long term anticoagulant therapy is hoped to be avoided. On the other hand, in recent, uncomplicated, non-valvular atrial fibrillation, a common fallacy should be corrected: transoesophageal echocardiography does not improve the safety of electrical cardioversion. With similar durations of prior anticoagulant therapy. Over a 3 week period, the frequency of thromboembolic complications is the same whether or not transoesophageal echocardiography is performed before cardioversion (0.8% in both groups of the SEIDL study). With short periods of anticoagulant therapy before cardioversion, there is a higher thromboembolic complication and mortality rate (ACUTE study). The safety of cardioversion is not related to the practice of prior transoesophageal echocardiography but to strict and efficacious anticoagulation for a period of 3 weeks before cardioversion.