title: Responses of normal subjects during 80 degrees head upright tilt table testing with and without low dose isoproterenol infusion.
abstract: Head upright tilt table testing has emerged as a standard technique for the evaluation of patients with recurrent unexplained syncope. To determine the specificity of head upright tilt table testing with and without a low dose isoproterenol infusion, the following study was undertaken. A total of 34 normal volunteers (21 men, 13 women, mean age 32.9 +/- 1.7 years) with no history of syncope, presyncope, or vertigo underwent head upright tilt table testing for 45 minutes. A positive test was defined as the production of syncope or presyncope associated with hypotension and bradycardia. If the test was negative the patient was lowered to the supine position and a low dose isoproterenol infusion started (sufficient to raise the heart rate 20-25% above baseline) and the patient retilted for 20 minutes. Three subjects (8.8%; 95% CI: 2, 26; P = 0.23) developed syncope during the test, two during the baseline tilt, and one during isoproterenol infusion. Interestingly, one of these subjects later had a clinical syncopal episode. We conclude that head up tilt table testing at 80 degrees with or with out low level isoproterenol infusion provides an adequate specificity.
authors.affiliation: Department of Medicine, Medical College of Ohio, Toledo 43699, USA.
authors.forename: B P
authors.initials: BP
authors.lastname: Grubb
authors.forename: D
authors.initials: D
authors.lastname: Kosinski
authors.forename: P
authors.initials: P
authors.lastname: Temesy-Armos
authors.forename: P
authors.initials: P
authors.lastname: Brewster
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D016001:Confidence Intervals; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007262:Infusions, Intravenous; D007545:Isoproterenol / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D013566:Sympathomimetics / Q000008:administration & dosage; D013575:Syncope / Q000209:etiology*; D018667:Tilt-Table Test
chemical_list: D013566:Sympathomimetics; D007545:Isoproterenol