Idiopathic atrial fibrillation as a risk factor for mortality - The Paris Prospective Study I

Aims Idiopathic atrial fibrillation describes atrial fibrillation of unknow n origin occurring without heart disease. Mortality is considered unaffecte d by idiopathic atrial fibrillation. We used the long follow-up period (23 years on average) of the Paris Prospective Study I to assess the mortality of idiopathic atrial fibrillation subjects in middle-aged men. Methods 7746 working Frenchmen, aged 43-52 in 1967-72, underwent a physical examination plus EGG, answered questionnaires, and provided blood samples. Strict exclusion criteria were used to select idiopathic atrial fibrillati on only, and men with known cardiac disease were further excluded from anal ysis. At 1 January 1994, vital status was unknown for 4.6% of the subjects. The analysis was conducted on the 6722 remaining subjects. Results Twenty-five subjects had idiopathic atrial fibrillation at inclusio n. The relative risk (and 95% confidence interval) associated with idiopath ic atrial fibrillation was 4.22 [2.10-8.47] for cardiovascular mortality (P =0.0001) and 1.97 [1.14-3.40] for total mortality (P=0.01). When age, systo lic blood pressure, cholesterol, body mass index and tobacco consumption we re entered into a Cox model, idiopathic atrial fibrillation remained an ind ependent risk factor for cardiovascular (P=0.0008) and total death (P=0.04) . Conclusion With a long follow-up period, idiopathic atrial fibrillation was associated with higher mortality in middle aged Frenchmen.