Restoring sinus rhythm is patients with non-valvular atrial fibrillation has two objectives: restore haemodynamic performance and reduce the risk of thromboembolism. Whether the cardioversion is spontaneous or induced with drugs or electroshock, the process itself carries the risk of systemic embolism attributed to the transitory inactivity of the left atrium. Current practice of giving anticoagulants at least 4 weeks before electric cardioversion is a compromise between the embolic risk of cardioversion estimated at 0.4 to 0.8% and haemorrhagic complications related to low blood coagulability estimated at about 1% per year. The advent of transoesophageal echography has made it possible to study the atrium in detail in search of thrombi. The result has been a revolution in our concepts and therapeutic approach to atrial fibrillation and cardioversion. Recent studies have shown that "rapid cardioversion" associated with minimal 48-hour anticoagulation with heparin IV and transoesophageal echography to eliminate a thrombus in the atrium and/or the atrial appendage can be proposed without increasing the risk of embolism. Besides simplifying the therapeutic protocols (but at the cost of the semiinvasive nature of the transoesophageal echocardiography), this method also has the merit of restoring atrial function rapidly, particularly in cases of recent onset arrhythmia.