title: Blood pressure oscillations during tilt testing as a predictive marker of vasovagal syncope.
abstract: OBJECTIVE
  During head-up tilt (HUT) testing, a period of haemodynamic instability, marked by oscillations in blood pressure, often precedes vasovagal syncope. We hypothesized that the presence of oscillations in blood pressure during HUT testing predicts a positive diagnosis for vasovagal syncope.
  
  
  RESULTS
  The haemodynamic profiles of 42 consecutive patients non-responsive to passive HUT and glyceryl trinitrate (GTN) provocation ('non-responders') and, contemporaneously, 41 consecutive patients responsive to passive HUT and GTN provocation ('responders') were assigned oscillation-positive or oscillation-negative depending on the presence or absence of a characteristic oscillation in systolic blood pressure which varied by > or =30 mmHg (peak-to-trough). All the non-responders proceeded to an isoprenaline (Iso) challenge test. Of the 42 non-responders, 27 patients were Iso tilt-positive; all of these patients were assigned oscillation-positive. The other 15 non-responders were Iso tilt-negative; of these 9 were assigned oscillation-positive and 6 were assigned oscillation-negative. Of the 41 responder patients, 33 were assigned oscillation-positive, whereas 8 were assigned oscillation-negative. Overall, the presence of oscillations as a diagnostic predictor for vasovagal syncope had a sensitivity of 88% (positive predictive value of 87%) and a specificity of 40% (negative predictive value of 43%).
  
  
  CONCLUSIONS
  In patients non-responsive to passive HUT and GTN provocation, the presence of an oscillating systolic blood pressure varying > or =30 mmHg may still indicate a diagnosis of vasovagal syncope, possibly obviating the need for Iso testing.
authors.affiliation: The Hatter Cardiovascular Institute, University College London Hospital and Medical School, 67 Chenies Mews, London, UK.
authors.forename: Derek John
authors.initials: DJ
authors.lastname: Hausenloy
authors.forename: Chanpreet
authors.initials: C
authors.lastname: Arhi
authors.forename: Navin
authors.initials: N
authors.lastname: Chandra
authors.forename: Ann-Christine
authors.initials: AC
authors.lastname: Franzen-McManus
authors.forename: Andrea
authors.initials: A
authors.lastname: Meyer
authors.forename: Richard
authors.initials: R
authors.lastname: Sutton
mesh_terms: D000328:Adult; D001795:Blood Pressure Determination / Q000379:methods*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009991:Oscillometry / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019462:Syncope, Vasovagal / Q000175:diagnosis*; D018667:Tilt-Table Test / Q000379:methods*