title: The yield of head-up tilt testing is not significantly increased by repeating the baseline test.
abstract: OBJECTIVE
  Head-up tilt is widely used in evaluating patients with syncope. Data suggest that baseline tilt without isoproterenol is associated with few (< or = 10%) positive results in normals. However, there is considerable day-to-day variability in patients with syncope, resulting in low reproducibility. We hypothesized that repeating the baseline tilt would increase the total number of positive responses.
  
  
  METHODS
  In all, 193 patients with syncope of unknown etiology prospectively underwent serial baseline tilt (Tilt-1 and Tilt-2) at 70 degrees for 25 min on two consecutive days.
  
  
  RESULTS
  Of 193 patients, 39 (20%) had a positive Tilt-1. Of these, 19 had a positive Tilt-2, (positive concordance rate: 19/39 = 49%). Of 154 patients with a negative Tilt-1, 145 had a negative Tilt-2 (negative concordance rate: 142/151 = 94%). Only 9 of 154 patients (6%) with a negative Tilt-1 had a positive Tilt-2. Thus, the yield increased from 20% (39/193) after Tilt-1, and to 25% (48/193) after Tilt-1 plus Tilt-2, p = NS.
  
  
  CONCLUSIONS
  (1) Reproducibility of a positive Tilt-1 is moderate. (2) Reproducibility of a negative Tilt-1 is high. (3) Repetition of tilt in patients with a negative Tilt-1 does not significantly increase the number of positive results.
authors.affiliation: Department of Medicine, Massachusetts General Hospital, Boston, USA.
authors.forename: B B
authors.initials: BB
authors.lastname: Pavri
authors.forename: J N
authors.initials: JN
authors.lastname: Ruskin
authors.forename: R
authors.initials: R
authors.lastname: Brooks
mesh_terms: D001794:Blood Pressure; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D011187:Posture / Q000502:physiology*; D011446:Prospective Studies; D015203:Reproducibility of Results; D019462:Syncope, Vasovagal / Q000175:diagnosis* / Q000503:physiopathology; D018667:Tilt-Table Test / Q000379:methods*