Heart Rate Variation in Females Predicts Tilt Test Results

Head-up tilt test (HUTT) is widely used to evaluate patients with unexplained syncope, but data on clinical predictors of HUTT results are limited. The investigators aim to evaluate heart rate (HR) variations and blood pressure (BP) changes associated with the HUTT results and the difference according to the gender. For this, a cross-sectional study will be performed with patients attended with unexplained syncope submitted to HUTT (70-degree angle), from January/2011 to April/2015. The investigators will analyze BP changes and Receiver-Operating Characteristics (ROC) curves for the maximum interval in HR variation from the first minute to tenth minute (delta-HR 10) after tilting. The significance level will be considered at 5%.