title: Prediction of head-up tilt test result by analysis of early heart rate variations.
abstract: BACKGROUND
  Head-up tilt testing is a useful test for investigating vasovagal syncope. The determination of early, accurate, predictive criteria for a negative result would permit a reduction in the duration of the tilt test.
  
  
  RESULTS
  Patients with no drug use and no illnesses other than recurrent unexplained syncope were recruited. In an initial study (110 consecutive patients), we aimed to determine a predictive criterion based on heart rate variations during the first minutes of upright tilting that could distinguish between patients with positive and negative tilt tests (patients with an early continual decrease in heart rate or blood pressure were excluded). Then we tested the predictive value of the established criterion in a second independent sample of patients with unexplained syncope (109 consecutive patients). An early sustained increase in heart rate < or = 18 bpm during the first 6 minutes of upright tilting at a 60 degree angle allowed us to predict negative tilt tests with 100% specificity, 100% positive predictive value, and 88.6% sensitivity. This criterion was validated in the second, prospective arm of the study (96.4% specificity, 98.4% positive predictive value, and 87.3% sensitivity), even with subsequent use of isoproterenol in low doses.
  
  
  CONCLUSIONS
  In patients with no drug use and no illnesses other than recurrent unexplained syncope, a simple clinical criterion identifies patients who will not develop syncope during a prolonged upright tilt.
authors.affiliation: Centre de Rythmologie et de Stimulation Cardiaque, Hôpital Jean Rostand, Ivry-sur-Seine, France.
authors.forename: Z
authors.initials: Z
authors.lastname: Mallat
authors.forename: E
authors.initials: E
authors.lastname: Vicaut
authors.forename: A
authors.initials: A
authors.lastname: Sangaré
authors.forename: J
authors.initials: J
authors.lastname: Verschueren
authors.forename: G
authors.initials: G
authors.lastname: Fontaine
authors.forename: R
authors.initials: R
authors.lastname: Frank
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D013575:Syncope / Q000503:physiopathology*; D018667:Tilt-Table Test