title: Predictors of response to the head-up tilt test in patients with unexplained syncope or presyncope.
abstract: BACKGROUND
  Unexplained syncope is a relatively frequent symptom, mostly caused by a neurocardiogenic reaction. The purpose of this study was to determine predictors of response to head-up tilt testing (HUTT) in patients with unexplained syncope or presyncope.
  
  
  METHODS
  HUTT was done in 640 consecutive patients with unexplained syncope or presyncope (393 men, mean age 45+/-19 years) after initial workup including history, physical examination, and appropriate laboratory evaluation.
  
  
  RESULTS
  Three hundred and forty-four (54%) patients had a positive result. The most common type of response was mixed type (46%) followed by vasodepressor (39%) and cardioinhibitory (15%) types. Age, gender, presence of structural heart disease, baseline heart rhythm, and the presenting symptom before the test failed to predict a positive response to HUTT, but among patients with a positive response to the test, age (OR: 1.54, CI = 1.04-2.47, P = 0.016) and presyncope (OR: 2.16, CI = 1.2-3.85, P = 0.008) as the presenting symptom predicted a vasodepressor type of response. The age (OR: 1.58, CI = 1.29-3.94, P = 0.01) and presyncope (OR: 4.6, CI = 1.74-12.24, P = 0.001) were also predictors for test positivity in the active stage.
  
  
  CONCLUSIONS
  There is an age-related gradient in hemodynamic response during neurocardiogenic syncope. The elderly patients more commonly had a vasodepressor and late response, in the active stage, but young subjects more commonly experienced an earlier and cardioinhibitory or mixed responses in the passive stage.
authors.affiliation: Department of Cardiology, Madani Cardiovascular Medical and Research Center, Tabriz University of Medical Sciences, Tabriz, Iran. bkazemia1966@gmail.com
authors.forename: Babak
authors.initials: B
authors.lastname: Kazemi
authors.forename: Majid
authors.initials: M
authors.lastname: Haghjoo
authors.forename: Arash
authors.initials: A
authors.lastname: Arya
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Sadr-Ameli
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005260:Female; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D015995:Prevalence; D011379:Prognosis; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D012680:Sensitivity and Specificity; D017678:Sex Distribution; D019462:Syncope, Vasovagal / Q000175:diagnosis* / Q000453:epidemiology*; D018667:Tilt-Table Test / Q000706:statistics & numerical data*