title: Effect of the September 11, 2001 terrorist attack on a state highway patrol trooper's heart rate variability.
abstract: BACKGROUND
  On September 11, 2001, terrorists attacked the United States. By coincidence, a North Carolina highway patrol trooper was wearing an ambulatory ECG Holter monitor at this time as part of an air pollution study.
  
  
  METHODS
  Heart rate variability parameters were analyzed: standard deviation of normal to normal beat intervals (SDNN) and percentage of interval differences >50 ms (PNN50).
  
  
  RESULTS
  The trooper's heart rate variability changed immediately after learning about the terrorist attacks. Heart rate increased and PNN50 decreased, while SDNN increased strongly.
  
  
  CONCLUSIONS
  These changes suggest strong emotional sympathetic stress associated with parasympathetic withdrawal in response to the news about the terrorist attack.
authors.affiliation: Center for Environmental Medicine, Asthma and Lung Biology School of Medicine, University of North Carolina, Chapel Hill, NC, USA. michael.riediker@alumni.ethz.ch
authors.forename: Michael
authors.initials: M
authors.lastname: Riediker
authors.forename: Margaret C
authors.initials: MC
authors.lastname: Herbst
authors.forename: Robert B
authors.initials: RB
authors.lastname: Devlin
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Griggs
authors.forename: Philip A
authors.initials: PA
authors.lastname: Bromberg
authors.forename: Wayne E
authors.initials: WE
authors.lastname: Cascio
mesh_terms: D015716:Electrocardiography, Ambulatory; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D009657:North Carolina; D016495:Police; D023481:Terrorism; D014481:United States