[Idiopathic atrial fibrillation: clinical and therapeutic problems]

Atrial fibrillation (AF) is defined as idiopathic when no one heart disease can be documented by clinical examination or by laboratory investigations. Epidemiological studies have shown that almost one third of all the cases of AF are idiopathic and that their incidence increases with age. Idiopathic AF may have different clinical manifestations: the paroxysmal form, characterised by long-lasting episodes, the transient recurrent form, characterised by frequent self-terminating episodes, or, less commonly, the chronic form. According to the literature, the risk of thromboembolic complications in idiopathic AF is not elevated and certainly lower than in AF associated with heart disease. By a clinical evaluation patients in whom an electrical cardioversion is necessary for reestablishing the sinus rhythm can be identified, considering that definite contraindications to electrical cardioversion exist. For prophylaxis of recurrences of AF the classical treatment with class 1A antiarrhythmic drugs (disopyramide or quinidine) is not very effective and not well tolerated; recently class 1C antiarrhythmic drugs have been employed with better results. In patients without heart failure their employment appears sufficiently safe. Amiodarone is certainly very effective but considering the serious side effects, its use must be limited to selected cases. Moreover non-pharmacological treatments (catheter ablation and surgery) have been developed recently for selected cases of AF refractory to antiarrhythmic drugs.