title: Shortened head-up tilt testing potentiated with sublingual nitroglycerin in patients with unexplained syncope.
abstract: BACKGROUND
  Head-up tilt testing is extensively used to determine the vasovagal origin of syncope in patients with otherwise unexplained loss of consciousness, although issues remain regarding the method of the test. The diagnostic value of a shortened head-up tilt test potentiated with sublingual nitroglycerin was assessed in patients with unexplained syncope.
  
  
  METHODS
  Two hundred two patients (mean age 49+/-19 years) with syncope of unknown origin and 34 subjects in a control group (mean age 45+/-17 years) were studied. The patients and the subjects in the control group were tilted upright to 60 degrees for 20 minutes. If syncope did not occur, sublingual nitroglycerin (400 microg) was administered, and observation was continued for 25 more minutes.
  
  
  RESULTS
  During the unmedicated phase syncope occurred in 22 (11%) patients and in one member of the control group. After nitroglycerin was administered, syncope occurred in 119 (59%) patients and in 1 (3%) member of the control group. False-positive response (exaggerated response) was observed in eight (4%) patients and in four (12%) subjects in the control group. The total positivity rate of the test was 70% with a specificity rate of 94%.
  
  
  CONCLUSIONS
  Short-duration head-up tilt test potentiated with sublingual nitroglycerin provides an adequate specificity and positivity rate in patients with unexplained syncope.
authors.affiliation: Division of Cardiology, Ospedale S. Pietro Igneo, Fucecchio, University of Florence, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Del Rosso
authors.forename: P
authors.initials: P
authors.lastname: Bartoli
authors.forename: A
authors.initials: A
authors.lastname: Bartoletti
authors.forename: A
authors.initials: A
authors.lastname: Brandinelli-Geri
authors.forename: F
authors.initials: F
authors.lastname: Bonechi
authors.forename: M
authors.initials: M
authors.lastname: Maioli
authors.forename: F
authors.initials: F
authors.lastname: Mazza
authors.forename: A
authors.initials: A
authors.lastname: Michelucci
authors.forename: L
authors.initials: L
authors.lastname: Russo
authors.forename: E
authors.initials: E
authors.lastname: Salvetti
authors.forename: M
authors.initials: M
authors.lastname: Sansoni
authors.forename: A
authors.initials: A
authors.lastname: Zipoli
authors.forename: A
authors.initials: A
authors.lastname: Fierro
authors.forename: A
authors.initials: A
authors.lastname: Ieri
mesh_terms: D000286:Administration, Sublingual; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure; D003937:Diagnosis, Differential; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D005996:Nitroglycerin / Q000008:administration & dosage; D015588:Observer Variation; D011187:Posture / Q000502:physiology*; D013575:Syncope / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D014630:Vagus Nerve / Q000187:drug effects; D014665:Vasodilator Agents / Q000008:administration & dosage
chemical_list: D014665:Vasodilator Agents; D005996:Nitroglycerin