Cardioversion of atrial fibrillation: the use of antiarrhythmic drugs

Atrial fibrillation (AF) is the commonest atrial arrhythmia and represents a large burden on modern health services. Large multicentre randomised trials have demonstrated that a rhythm control strategy (using antiarrhythmic drugs and direct current (DC) cardioversion) has no morbidity or mortality advantage over rate control. Therefore, for most patients, attempts to cardiovert AF to sinus rhythm (SR) should be reserved for those patients who are symptomatic despite adequate rate control. For recent-onset AF (<24 h) the use of agents like flecainide can be highly successful to pharmacologically cardiovert AF, although caution should be exercised in patients who have the potential for structural or coronary artery disease because of the risk of proarrhythmia. If there any is doubt as to the suitability of a patient for pharmacological cardioversion then DC cardioversion is the safer option. Owing to the high recurrence rate of AF after cardioversion (71-84% at 1 year), the use of antiarrhythmic drugs to maintain SR is recommended. The irreversible side effects of amiodarone mean that it should be avoided whenever possible for long-term maintenance treatment, although it is useful in short courses (8 weeks-6 months), particularly for patients who had a successfully treated secondary cause for AF. Other agents like flecainide and sotalol are also useful but should not be used for patients with structural heart disease. Data supporting the use of newer agents like dronedarone are at present limited.