title: Age and the Head-Up Tilt Test Outcome in Syncope Patients.
abstract: BACKGROUND
  The head-up tilt test (HUTT) is a useful diagnostic tool for syncope.
  
  
  OBJECTIVE
  We sought to investigate the outcome of the HUTT in syncope patients and identify the relationship between age and different hemodynamic outcomes.
  
  
  METHODS
  In this cross-sectional study, we prospectively enrolled consecutive patients who presented with syncope and underwent the HUTT with a clinical suspicion of neurocardiogenic syncope after the exclusion of orthostatic hypotension cases. The HUTT consisted of consecutive passive and active phases. In the passive phase, the patients were tilted at 70 degrees for 20 minutes; and if negative, the test was repeated with 400 micrograms of sublingual nitroglycerin for another 20 minutes. Positive responses were classified according to the classification of the vasovagal syncope international study (VASIS) and compared for age and gender.
  
  
  RESULTS
  A total of 498 patients were enrolled (age = 44.93 ± 18.77 years; male = 271 [54.4%]). Overall, 291 (58.4%) patients had a positive HUTT, while 256 (88.5%) patients had a positive result during the active phase. The test results were as follows: 107 (36.7%) mixed type (VASIS I), 103 (35.3%) cardioinhibitory (VASIS IIA = 44 [15.1%]; VASIS IIB = 59 [20.2%]), and 80 (27.4%) vasodepressive (VASIS III). There was no relationship between gender and syncope type. The trend of the HUTT result significantly changed with age, and the rate of cardioinhibitory syncope decreased after middle ages (P value for trend = 0.02).
  
  
  CONCLUSIONS
  Hemodynamic response to the HUTT was associated with age. Cardioinhibitory response became less frequent with age due to exaggerated vagal activity in the younger patients as compared with the older subjects.
authors.affiliation: Tehran Heart Center, Tehran University of Medical Sciences, Tehran, IR Iran.
authors.forename: Rezvan
authors.initials: R
authors.lastname: Noormand
authors.affiliation: Tehran Heart Center, Tehran University of Medical Sciences, Tehran, IR Iran.
authors.forename: Akbar
authors.initials: A
authors.lastname: Shafiee
authors.affiliation: Tehran Heart Center, Tehran University of Medical Sciences, Tehran, IR Iran.
authors.forename: Gholamreza
authors.initials: G
authors.lastname: Davoodi
authors.affiliation: Tehran Heart Center, Tehran University of Medical Sciences, Tehran, IR Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Tavakoli
authors.affiliation: Tehran Heart Center, Tehran University of Medical Sciences, Tehran, IR Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Gheini
authors.affiliation: Tehran Heart Center, Tehran University of Medical Sciences, Tehran, IR Iran.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Yaminisharif
authors.affiliation: Tehran Heart Center, Tehran University of Medical Sciences, Tehran, IR Iran.
authors.forename: Arash
authors.initials: A
authors.lastname: Jalali
authors.affiliation: Tehran Heart Center, Tehran University of Medical Sciences, Tehran, IR Iran.
authors.forename: Saeed
authors.initials: S
authors.lastname: Sadeghian
keywords: Age Groups; Diagnosis; Syncope; Tilt-Table Test; Vasovagal Syncope