title: Utility of upright tilt-table testing in the evaluation and management of syncope of unknown origin.
abstract: OBJECTIVE
  Vasovagally mediated hypotension and bradycardia are believed to be common, but difficult to diagnose, causes of syncope. Upright tilt-table testing has been proposed as a possible way to test for vasovagal episodes. This study investigated the clinical utility of this technique in the evaluation and management of patients with syncope of unknown origin.
  
  
  METHODS
  Twenty-five patients with recurrent unexplained syncope and six control subjects were evaluated by use of an upright tilt-table test for 30 minutes, with or without an infusion of isoproterenol (1 to 3 micrograms/minute given intravenously), in an attempt to provoke bradycardia, hypotension, or both. Of the 25 patients, there were 14 males and 11 females, with a mean age of 50 +/- 16 years. Six control patients with no history of syncope were also studied. All tilt-positive patients received therapy with either beta-blockers, disopyramide, transdermal scopolamine, or hydroflurocortisone, the efficacy of which was evaluated by another tilt-table test.
  
  
  RESULTS
  Syncope occurred in six patients (24%) during the baseline tilt and in nine patients (36%) during isoproterenol infusion (total positives, 60%). None of the controls had syncope during the test. All patients who had positive test results eventually became tilt-table-negative by therapy, and over a mean follow-up period of 16 +/- 2 months no further episodes have occurred.
  
  
  CONCLUSIONS
  From this study we conclude that upright tilt-table testing combined with isoproterenol infusion is clinically useful in the diagnosis of vasovagal syncope and the evaluation of pharmacologic therapy.
authors.affiliation: Department of Medicine, Medical College of Ohio, Toledo 43699.
authors.forename: B P
authors.initials: BP
authors.lastname: Grubb
authors.forename: P
authors.initials: P
authors.lastname: Temesy-Armos
authors.forename: H
authors.initials: H
authors.lastname: Hahn
authors.forename: L
authors.initials: L
authors.lastname: Elliott
mesh_terms: D000293:Adolescent; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004206:Disopyramide / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007545:Isoproterenol; D008297:Male; D008722:Methods; D008875:Middle Aged; D011187:Posture; D012008:Recurrence; D012601:Scopolamine / Q000627:therapeutic use; D013575:Syncope / Q000175:diagnosis* / Q000188:drug therapy / Q000209:etiology
chemical_list: D000319:Adrenergic beta-Antagonists; D012601:Scopolamine; D004206:Disopyramide; D007545:Isoproterenol