title: Risk factors for syncope recurrence after a positive tilt-table test in patients with syncope.
abstract: BACKGROUND
  Recent work with head-up tilt-table testing has suggested that many patients with syncope may have recurrent neurally mediated episodes of bradycardia, hypotension, or both. The purpose of this study was to determine how to identify patients at high risk of a recurrence of neuromediated syncope after a positive isoproterenol/tilt-table test.
  
  
  RESULTS
  A cohort of 101 drug-free patients in a university hospital outpatient clinic with syncope and a positive isoproterenol/tilt-table test underwent baseline assessment of demographic variables, symptomatic burden, and hemodynamic and clinical responses to tilt testing. The primary outcome measure was the time to the first recurrent syncopal spell. The actuarial probabilities of remaining syncope free after 1 and 2 years were 72% and 60%, respectively. Multivariate proportional hazards analysis demonstrated that the most powerful predictor of a recurrence of syncope was the logarithm of the number of preceding syncopal spells (P<.001). Other predictive variables included the duration of syncopal symptoms, tilt test symptomatic outcome, and trough heart rate. The probability of a recurrence of syncope also varied with the logarithm of the frequency of preceding spells (P=.008). The median frequency of pretest spells was 0.3/month; after the tilt test, the median frequency dropped approximately 90% to 0.03 per month.
  
  
  CONCLUSIONS
  The risk of a recurrence of syncope after a positive tilt-table test can be predicted with simple pretest and intratest variables.
authors.affiliation: Cardiovascular Research Group, University of Calgary, Alberta, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Sheldon
authors.forename: S
authors.initials: S
authors.lastname: Rose
authors.forename: P
authors.initials: P
authors.lastname: Flanagan
authors.forename: M L
authors.initials: ML
authors.lastname: Koshman
authors.forename: S
authors.initials: S
authors.lastname: Killam
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007545:Isoproterenol; D008297:Male; D015233:Models, Statistical; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D012008:Recurrence; D012307:Risk Factors; D013575:Syncope / Q000175:diagnosis*; D018667:Tilt-Table Test; D013997:Time Factors
chemical_list: D007545:Isoproterenol