title: Sublingual nitrates during head-up tilt testing for the diagnosis of vasovagal syncope.
abstract: Pharmacologic stimulation during head-up tilt test (HUT) is used to increase the diagnostic yield of the test to detect vasovagal syncope. Reported lack of specificity of stimulation with intravenous isoproterenol has made a pharmacologic alternative desirable. Because nitrates are known to cause syncope of a vasovagal origin, we administered sublingual nitrates after classic tilt test in 32 patients with a history of typical vasovagal syncope and 20 healthy volunteers to assess the sensitivity, specificity, and accuracy of this new HUT technique. During the classic HUT four (13%) patients had syncope; after administration of sublingual nitrates, this number increased to 28 (87%). In the control group no subject had syncope during classic HUT, whereas during nitrate administration six (30%) had syncope. Sublingual nitrate stimulated HUT revealed a maximum accuracy of 83% at a cutoff point of 11 minutes, giving a sensitivity of 81% and specificity of 85%. Sublingual nitrate administration increased the accuracy of HUT in diagnosing vasovagal syncope in patients with a history of typical vasovagal syncope.
authors.affiliation: Department of Cardiology, University Hospital, Free University of Brussels, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Aerts
authors.forename: P
authors.initials: P
authors.lastname: Dendale
authors.forename: G
authors.initials: G
authors.lastname: Strobel
authors.forename: P
authors.initials: P
authors.lastname: Block
mesh_terms: D000286:Administration, Sublingual; D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007548:Isosorbide Dinitrate / Q000008:administration & dosage; D008297:Male; D012680:Sensitivity and Specificity; D019462:Syncope, Vasovagal / Q000175:diagnosis*; D018667:Tilt-Table Test / Q000379:methods*; D014665:Vasodilator Agents / Q000008:administration & dosage
chemical_list: D014665:Vasodilator Agents; D007548:Isosorbide Dinitrate