Abstract 14005: Beat-to-beat Variability of Hemodynamic Parameters Predict the Outcomes of Head Up Tilt Table Test in Patients With Vasovagal Syncope

Abstract

Introduction: The risk of severe syncopal episodes during head up tilt table test (HUTT) in patients with vasovagal syncope (VVS) limits its use in clinic. The objective of this study was to identify the early hemodynamic predictors of positive results during HUTT. Methods: HUTT was conducted prospectively in 82 consecutive patients with suspicious VVS and 19 normal control. Continuous noninvasive hemodynamic monitor was used to monitor the beat-to-beat changes of heart rate (HR) and blood pressure (BP). Values of short-term heart rate variability (HRV) and blood pressure variability (BPV) were calculated using formula of HR(BP)V= Σ ∣ HR(BP)n+1-HR(BP)n ∣ /(n x √2). Receiver-operating characteristic (ROC) curve analysis was used to test the predictive values. Results: Fifty-six out of 82 patients were HUTT positive. The results indicated that four parameters, including percentage of HR increment (ΔHR%) and systolic BPV increment (ΔSBPV%) were early (5 minutes after tilt-up), the ΔSBPV% and percentage of mean arterial pressure variability increment (ΔMAPV%) were late (30 minutes after tilt-up) predictors of a syncopal episode during HUTT. The detailed predictive information of these parameters were listed in table 1. Conclusion: Beat-to-beat variability of HR, SBPV and MAPV increment during early and late tilt-up period are valuable pre-syncopal parameters to predict the outcome of HUTT in patients with VVS.