title: Cardiac Autonomic Dysfunction and Incidence of Atrial Fibrillation: Results From 20 Years Follow-Up.
abstract: BACKGROUND
  Cardiac autonomic perturbations frequently antecede onset of paroxysmal atrial fibrillation (AF). Interventions that influence autonomic inputs to myocardium may prevent AF. However, whether low heart rate or heart rate variability (HRV), which are noninvasive measures of cardiac autonomic dysfunction, are associated with AF incidence is unclear.
  
  
  OBJECTIVE
  This study sought to study the association between HRV and risk of AF.
  
  
  METHODS
  This study included 11,715 middle-aged adults in the ARIC (Atherosclerosis Risk In Communities) cohort with heart rate and HRV measures obtained from 2-min electrocardiogram recordings performed at baseline (1987 to 1989). These measures included SD of normal-to-normal RR intervals, high-frequency (HF) (0.15 to 0.40 Hz), low-frequency (0.04 to 0.15 Hz), and the low-frequency/HF ratio (denoting a greater sympathetic to parasympathetic dominance). Incident AF cases were ascertained by electrocardiogram at ARIC follow-up visits, hospital discharge diagnosis, or death certificates through 2011.
  
  
  RESULTS
  During an average follow-up of 19.4 years, 1,580 or 13.5% of participants developed AF. A baseline heart rate <60 beats/min was associated modestly with an increased risk of AF. Lower overall HRV as well as increased sympathetic/parasympathetic tone were associated independently with a higher risk of AF; the hazard ratio for each 1 SD lower SD of normal-to-normal RR intervals was 1.14 (95% confidence interval: 1.08 to 1.21), for HF was 1.12 (95% confidence interval: 1.06 to 1.17), and for low frequency/HF was 1.08 (95% confidence interval: 1.03 to 1.14).
  
  
  CONCLUSIONS
  Cardiac autonomic dysfunction denoted by low resting short-term HRV was associated with higher AF incidence. A low heart rate may be associated with higher AF risk. Further studies are needed to determine whether interventions in the general population to restore autonomic balance may prevent AF.
authors.affiliation: Cardiovascular Institute, Mount Sinai School of Medicine, New York, New York; Division of General Internal Medicine and Epidemiology, Johns Hopkins University, Baltimore, Maryland. Electronic address: sunilagarwal1@gmail.com.
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Agarwal
authors.affiliation: Department of Epidemiology and Cardiology, University of Minnesota, Minneapolis, Minnesota.
authors.forename: Faye L
authors.initials: FL
authors.lastname: Norby
authors.affiliation: Department of Epidemiology and Medicine, University of North Carolina, Chapel Hill, North Carolina.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Whitsel
authors.affiliation: Department of Epidemiology and Prevention, Wake Forest School of Medicine, Winston-Salem, North Carolina.
authors.forename: Elsayed Z
authors.initials: EZ
authors.lastname: Soliman
authors.affiliation: Cardiovascular Division, Department of Medicine, University of Minnesota Medical School, Minneapolis, Minnesota.
authors.forename: Lin Y
authors.initials: LY
authors.lastname: Chen
authors.affiliation: Department of Epidemiology and Medicine, University of North Carolina, Chapel Hill, North Carolina.
authors.forename: Laura R
authors.initials: LR
authors.lastname: Loehr
authors.affiliation: Cardiovascular Institute, Mount Sinai School of Medicine, New York, New York.
authors.forename: Valentin
authors.initials: V
authors.lastname: Fuster
authors.affiliation: Department of Epidemiology and Medicine, University of North Carolina, Chapel Hill, North Carolina.
authors.forename: Gerardo
authors.initials: G
authors.lastname: Heiss
authors.affiliation: Division of General Internal Medicine and Epidemiology, Johns Hopkins University, Baltimore, Maryland.
authors.forename: Josef
authors.initials: J
authors.lastname: Coresh
authors.affiliation: Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Alonso
mesh_terms: D000328:Adult; D001281:Atrial Fibrillation / Q000209:etiology*; D001342:Autonomic Nervous System Diseases / Q000150:complications* / Q000503:physiopathology; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006331:Heart Diseases / Q000150:complications* / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged
keywords: arrhythmia; frequency; heart rate variability; parasympathetic; sympathetic