[Mid-term clinical and prognostic evaluation of idiopathic atrial fibrillation].

Forty-six patients with idiopathic or lone atrial fibrillation (AF) underwent clinical evaluation in the cardiology outpatient department. The follow-up period was 4.6 +/- 2.5 years. The prevalence of idiopathic AF was 19% (89% paroxysmal and 11% permanent) in a population of 244 patients with atrial fibrillation. The global prevalence was 1.15% out of 4,000 patients examined over the same period. A history of paroxysmal atrial fibrillation over a 6 +/- 4 year period was obtained in 61% of the patients with idiopathic AF before the study. At inclusion, 24% of patients were asymptomatic. During follow-up, 12 patients (26%) developed cardiovascular disease and/or hypertension. The size of the left atrium was measured by echocardiography in 45 patients and reevaluated in 30 of them during follow-up without any statistically significant difference being observed between the two values. There were no thromboembolic complications or deaths during follow-up. These results show that idiopathic AF is not uncommon in cardiology clinics. The evolution of the paroxysmal forms is variable--but the medium-term prognosis is excellent. In some cases, idiopathic AF may be a manifestation of asymptomatic coronary artery disease but the relationship between the two pathologies has not been definitely established.