title: Risk of atrial fibrillation as a function of the electrocardiographic PR interval: results from the Copenhagen ECG Study.
abstract: BACKGROUND
  Prolongation of the PR interval has been associated with an increased risk of incident atrial fibrillation (AF).
  
  
  OBJECTIVE
  To determine if there was a nonlinear relation between PR interval duration and the risk of AF.
  
  
  METHODS
  We included 288,181 individuals, corresponding to one third of the population in the greater region of Copenhagen. These individuals had a digital electrocardiogram (ECG) recorded in a general practitioner's core facility from 2001 to 2010. Data on drug use, comorbidity, and outcomes were collected from Danish registries.
  
  
  RESULTS
  During a median follow-up period of 5.7 years, 11,087 developed AF. Having a PR interval ≥95th percentile (≥196 ms for women, ≥204 ms for men) was associated with an increased risk of AF as evidenced by a multivariable-adjusted hazard ratio (HR) of 1.18 (95% confidence interval [CI] 1.06-1.30, P = .001) for women and 1.30 (1.17-1.44, P < .001) for men compared with the respective reference groups (PR interval between 40th and 60th percentile). Having a short PR interval <5th percentile (≤121 ms for women, ≤129 ms for men) was also associated with an increased risk of AF for women (HR 1.32, 95% CI 1.12-1.56, P = .001), but this was not significant for men (HR 1.09, 95% CI 0.92-1.29, P = .33).
  
  
  CONCLUSIONS
  In this large ECG study, we found an increased risk of AF for longer PR intervals for both women and men. With respect to short PR intervals, we also observed an increased risk of AF for women.
authors.affiliation: Danish National Research Foundation Centre for Cardiac Arrhythmia (DARC), Copenhagen, Denmark. jonas.bille.nielsen@gmail.com
authors.forename: Jonas Bille
authors.initials: JB
authors.lastname: Nielsen
authors.forename: Adrian
authors.initials: A
authors.lastname: Pietersen
authors.forename: Claus
authors.initials: C
authors.lastname: Graff
authors.forename: Bent
authors.initials: B
authors.lastname: Lind
authors.forename: Johannes Jan
authors.initials: JJ
authors.lastname: Struijk
authors.forename: Morten Salling
authors.initials: MS
authors.lastname: Olesen
authors.forename: Stig
authors.initials: S
authors.lastname: Haunsø
authors.forename: Thomas Aalexander
authors.initials: TA
authors.lastname: Gerds
authors.forename: Patrick Thomas
authors.initials: PT
authors.lastname: Ellinor
authors.forename: Lars
authors.initials: L
authors.lastname: Køber
authors.forename: Jesper Hastrup
authors.initials: JH
authors.lastname: Svendsen
authors.forename: Anders Gaarsdal
authors.initials: AG
authors.lastname: Holst
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000453:epidemiology / Q000503:physiopathology*; D003718:Denmark / Q000453:epidemiology; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006329:Heart Conduction System / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012042:Registries; D012307:Risk Factors; D012737:Sex Factors; D014505:Urban Population / Q000706:statistics & numerical data
keywords: AF; AV; Atrial fibrillation; BMI; CGPL; CI; Copenhagen General Practitioners’ Laboratory; ECG; Electrocardiography; Gender differences; General population; HR; IQR; Marquette 12SL validation; PR interval; WPW; Wolff-Parkinson-White; atrial fibrillation; atrioventricular; body mass index; confidence interval; electrocardiogram; hazard ratio; interquartile range