title: Idiopathic atrial fibrillation revisited in a large longitudinal clinical cohort.
abstract: OBJECTIVE
  An age of 60 years is often used as cut-off for the diagnosis of idiopathic atrial fibrillation (AF). We investigated the importance of age and atrial size in patients with idiopathic AF and AF patients with isolated hypertension.
  
  
  RESULTS
  Out of 3978 AF patients in the Euro Heart Survey on AF with known follow-up, 119 (3%) patients had idiopathic AF. We disregarded age and atrial size when selecting idiopathic AF patients since the atria may enlarge by AF itself. For comparison, we selected 152 patients with isolated hypertension from the database. A total of 57 (48%) of the patients were older than 60 years. Persistent or permanent AF was more prevalent in the older idiopathic AF patients (34% in the age <60 vs. 66% in the age >60 years group, P= 0.002) but mean duration of known AF did not differ between these groups [310 days (inter-quartile range, IQR) 60-1827) vs. 430 days (IQR 88-1669), P= 0.824]. Left atrial size did not differ significantly in relation to age (1.50 ± 0.29 mm/kg/m² in the age <60 vs. 1.56 ± 0.31 mm/kg/m² in the age >60 years group, P= 0.742). Only two paroxysmal AF patients progressed to permanent AF. No cardiovascular events occurred during the 1-year follow-up. In contrast, strokes occurred in five patients (6%) with isolated hypertension despite similar clinical profile and comparable atrial size as idiopathic AF patients.
  
  
  CONCLUSIONS
  Idiopathic AF may present at advanced age and is even then not associated with significant atrial enlargement, AF progression, or an adverse short-term prognosis. In contrast, elevated blood pressure even when found in the absence of significant atrial remodelling, seems of prognostic importance.
authors.affiliation: Department of Cardiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, PO Box 5800, Maastricht 6202 AZ, The Netherlands. b.weijs@mumc.nl
authors.forename: Bob
authors.initials: B
authors.lastname: Weijs
authors.forename: Ron
authors.initials: R
authors.lastname: Pisters
authors.forename: Robby
authors.initials: R
authors.lastname: Nieuwlaat
authors.forename: Günter
authors.initials: G
authors.lastname: Breithardt
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Le Heuzey
authors.forename: Panos E
authors.initials: PE
authors.lastname: Vardas
authors.forename: Ione
authors.initials: I
authors.lastname: Limantoro
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schotten
authors.forename: Gregory Y H
authors.initials: GY
authors.lastname: Lip
authors.forename: Harry J G M
authors.initials: HJ
authors.lastname: Crijns
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D015331:Cohort Studies; D015897:Comorbidity; D005060:Europe / Q000453:epidemiology; D006325:Heart Atria / Q000000981:diagnostic imaging*; D006801:Humans; D006973:Hypertension / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D008137:Longitudinal Studies; D008875:Middle Aged; D009929:Organ Size; D015995:Prevalence; D011379:Prognosis; D018570:Risk Assessment; D012307:Risk Factors; D017678:Sex Distribution; D014463:Ultrasonography