title: A comparison of a single-stage isoproterenol tilt table test protocol with conventional two-staged tilt protocol in patients with syncope.
abstract: OBJECTIVE
  Recently, Shen and colleagues described a single-stage isoproterenol protocol: Head Up Tilt Table testing (HUTT). The purpose of this study was to compare the introduction of this single-stage tilt protocol to sequential two-staged tilt table testing.
  
  
  METHODS
  Patients with recurrent or dramatic syncope or near syncope were referred for HUTT. A total of 100 patients underwent HUTT via a two-staged tilt protocol: 60  passive tilt for 30 minutes and, if negative, followed by a 10-minute tilt with isoproterenol titration to a 20% heart rate increase (two-staged HUTT). The next 100 patients underwent single stage isoproterenol protocol, which consisted of a 10-minute, 70  tilt with fixed dose isoproterenol infusion (0.05 ug/kg/minute). Patients with isoproterenol contraindications underwent a passive tilt (40 minutes for a conventional two-staged 60-degree tilt, and 45 minutes for a single-staged 70  tilt.
  
  
  RESULTS
  In the single-stage method, 40% of those that received isoproterenol had a positive test, as compared to 24% for two-stage HUTT protocol (p < 0.001).
  
  
  CONCLUSIONS
  A single-staged isoproterenol HUTT provides a rapid method of increasing the overall test yield as compared to conventional two-staged HUTT. Further research is necessary to elucidate the overall utility of this rapid single-stage protocol.
authors.affiliation: Electrophysiology Section in the Cardiology Division of the Department of Medicine, Winthrop University Hospital, New York, NY 11501, USA. Tcohen@winthrop.org
authors.forename: Todd J
authors.initials: TJ
authors.lastname: Cohen
authors.forename: Thomas
authors.initials: T
authors.lastname: Chengot
authors.forename: Marilyn
authors.initials: M
authors.lastname: Chengot
authors.forename: Sheila
authors.initials: S
authors.lastname: Catania
authors.forename: Weilun
authors.initials: W
authors.lastname: Quan
mesh_terms: D005260:Female; D006801:Humans; D007545:Isoproterenol; D008297:Male; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013575:Syncope / Q000175:diagnosis*; D018667:Tilt-Table Test / Q000379:methods*
chemical_list: D007545:Isoproterenol