title: Supine vs semirecumbent and upright 12-lead electrocardiogram: does change in body position alter the electrocardiographic interpretation for ischemia?
abstract: OBJECTIVE
  The goal of this study was to determine if a change in body position alters the 12-lead electrocardiographic (ECG) interpretation for ischemia and ST-segment elevation, the latter having direct implications for initial patient management in the emergency department.
  
  
  METHODS
  Twelve-lead ECGs were sequentially obtained from a convenience sample of healthy adult volunteers in 3 positions (supine, 0 degrees; inclined, 45 degrees; and upright, 90 degrees). The tracings were randomized, blinded, and then independently read by 2 trained emergency medicine physicians who also assessed for the presence of ischemia and ST-segment elevation myocardial infarction.
  
  
  RESULTS
  Seventy-five subjects were enrolled, with 7 (9%; 95% confidence interval [CI], 4-18) having ischemia on the supine ECG, 9 (12%; 95% CI, 6-22) on the incline, and 9 on the upright tracings. ST-segment elevation myocardial infarction pattern was present on 2 (3%; 95% CI, 0-9) supine, 2 inclined, and 2 upright ECGs.
  
  
  CONCLUSIONS
  Changes in body position result in some ischemic variations of the 12-lead ECG.
authors.affiliation: Department of Emergency Medicine, Tufts University School of Medicine, Baystate Medical Center, Springfield, MA 01199, USA. robert.baevsky@bhs.org
authors.forename: Robert H
authors.initials: RH
authors.lastname: Baevsky
authors.forename: Marc D
authors.initials: MD
authors.lastname: Haber
authors.forename: Fidela S
authors.initials: FS
authors.lastname: Blank
authors.forename: Howard
authors.initials: H
authors.lastname: Smithline
mesh_terms: D000328:Adult; D000368:Aged; D004562:Electrocardiography / Q000379:methods*; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000175:diagnosis* / Q000503:physiopathology*; D015588:Observer Variation; D011187:Posture; D011237:Predictive Value of Tests; D016037:Single-Blind Method