ATRIAL-FIBRILLATION - CONVERSION TO SINUS RHYTHM

Conversion to sinus rhythm (cardioversion) is recommended to prevent t he haemodynamic and thromboembolic complications of atrial fibrillatio n. Prior anticoagulation is compulsory except in emergencies. The dura tion of anticoagulant therapy depends on the terrain and chronicity of the arrhythmia. Cardioversion may be proposed for the majority of pat ients in whom it is thought that sinus rhythm can be maintained by app ropriate therapy. It may be carried out pharmacologically by oral or i ntravenous antiarrhythmic therapy. Amiodarone is the drug of choice. C ardioversion may also be carried out by external or internal direct cu rrent shock. The success rate of external electrical defibrillation de pends on the energy administered, the site of the electrodes and a num ber of factors related to thoracic impedence. Internal electrical defi brillation may be performed with an endocavitary catheter or by the oe sophageal approach, with few complications. The main problem resides i n maintaining sinus rhythm in the long term. When this is not possible , cardioversion is useless, and therapy to slow the cardiac rhythm sho uld be instituted.