title: Is syncope related to moderate altitude exposure?
abstract: OBJECTIVE
  To investigate factors related to syncope occurring on recent ascent to moderate altitude.
  
  
  METHODS
  A 1-year retrospective case-control study, using local acclimatized residents as a control group.
  
  
  METHODS
  The two main ambulance destinations for Summit County, Colorado (elevation, 2770 m).
  
  
  METHODS
  All patients with a diagnosis of syncope, near-syncope, or fainting whose medical records were available for review.
  
  
  RESULTS
  There was a significant relationship (P less than .05) between syncope of unknown origin and recent arrival at altitude (less than 24 hours), and a significant inverse relationship (P less than .05) between syncope of unknown origin and arterial oxygen saturation as measured by pulse oximetry.
  
  
  CONCLUSIONS
  Short-term exposure to moderate altitude may be related to otherwise unexplained syncope in healthy young adults. We suggest the name high-altitude syncope for this entity and encourage further research in this area.
authors.affiliation: Colorado Altitude Research Institute, Snake River Health Services, Keystone 80435.
authors.forename: R
authors.initials: R
authors.lastname: Nicholas
authors.forename: P D
authors.initials: PD
authors.lastname: O'Meara
authors.forename: N
authors.initials: N
authors.lastname: Calonge
mesh_terms: D000064:Acclimatization; D000328:Adult; D000531:Altitude; D000704:Analysis of Variance; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D010100:Oxygen / Q000097:blood; D012189:Retrospective Studies; D013575:Syncope / Q000209:etiology*
chemical_list: D010100:Oxygen