title: Drier air, lower temperatures, and triggering of paroxysmal atrial fibrillation.
abstract: BACKGROUND
  The few previous studies on the onset of paroxysmal atrial fibrillation and meteorologic conditions have focused on outdoor temperature and hospital admissions, but hospital admissions are a crude indicator of atrial fibrillation incidence, and studies have found other weather measures in addition to temperature to be associated with cardiovascular outcomes.
  
  
  METHODS
  Two hundred patients with dual chamber implantable cardioverter-defibrillators were enrolled and followed prospectively from 2006 to 2010 for new onset episodes of atrial fibrillation. The date and time of arrhythmia episodes documented by the implanted cardioverter-defibrillators were linked to meteorologic data and examined using a case-crossover analysis. We evaluated associations with outdoor temperature, apparent temperature, air pressure, and three measures of humidity (relative humidity, dew point, and absolute humidity).
  
  
  RESULTS
  Of the 200 enrolled patients, 49 patients experienced 328 atrial fibrillation episodes lasting ≥30 seconds. Lower temperatures in the prior 48 hours were positively associated with atrial fibrillation. Lower absolute humidity (ie, drier air) had the strongest and most consistent association: each 0.5 g/m decrease in the prior 24 hours increased the odds of atrial fibrillation by 4% (95% confidence interval [CI]: 0%, 7%) and by 5% (95% CI: 2%, 8%) for exposure in the prior 2 hours. Results were similar for dew point but slightly weaker.
  
  
  CONCLUSIONS
  Recent exposure to drier air and lower temperatures were associated with the onset of atrial fibrillation among patients with known cardiac disease, supporting the hypothesis that meteorologic conditions trigger acute cardiovascular episodes.
authors.affiliation: From the aDepartment of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY; bCardiac Arrhythmia Service, Division of Cardiology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA; cDepartment of Environmental Health, dDepartment of Epidemiology, Harvard School of Public Health, Boston, MA; eChanning Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA; and fCardiovascular Epidemiology Research Unit, Beth Israel Deaconess Medical Center, Boston, MA.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Nguyen
authors.forename: Mark S
authors.initials: MS
authors.lastname: Link
authors.forename: Heike
authors.initials: H
authors.lastname: Luttmann-Gibson
authors.forename: Francine
authors.initials: F
authors.lastname: Laden
authors.forename: Joel
authors.initials: J
authors.lastname: Schwartz
authors.forename: Benjamin S
authors.initials: BS
authors.lastname: Wessler
authors.forename: Murray A
authors.initials: MA
authors.lastname: Mittleman
authors.forename: Diane R
authors.initials: DR
authors.lastname: Gold
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Dockery
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000209:etiology*; D001900:Boston / Q000453:epidemiology; D003080:Cold Temperature / Q000009:adverse effects*; D017147:Defibrillators, Implantable; D005260:Female; D006801:Humans; D006813:Humidity / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D014887:Weather