Haemodynamic Responses and Effectiveness of Head Upright Tilt Test in Unexplained Syncope in Children

Background: Vasovagal syncope is a benign condition, defined as a transient loss of consciousness and postural tone due to cerebral hypoperfusion. The Head Upright Tilt Test (HUTT) is widely used and has proven to be a practical tool for the diagnosis and treatment of syncope. In this study, we evaluated various hemodynamic responses obtained from the Head Upright Tilt Test and usefulness of HUTT in training for possible prevention of syncope in pediatric population. Methods: A total of 75 consecutive subjects aged 5 to 20-years affected by syncope or near syncope underwent head upright tilt testing over a 5-year period, from the single centre data base study between 2015 and 2019. Test results were classified as negative or positive. Positive cases were further classified into vaso-depressive, vasoinhibitory, and mixed hemodynamic reactions and were also followed up prospectively over a 3-year period. Results: Of the 75 cases studied 50.7% male and 49.3% female. Positives were 69.3% (n=52), and the remaining cases were negative for vaso-vagal syncope. Among HUTT-positive cases, the most common hemodynamic responses in the pediatric population were of the mixed type (52%), followed by the vasodepressive type (40%), vasoinhibitory (6%), and psychogenic causes (2%). HUTT-positive cases were followed up for 3-years, and the majority of patients (77%) had no significant symptoms during the follow-up in our syncope evaluation clinic. Conclusion: HUTT is an important investigation to differentiate unexplained syncope from other causes of unconsciousness in the pediatric population. The most common hemodynamic reactions obtained in tilt test were of the mixed type, followed by the vasodepressive type. The HUTT test may also be considered as training for possible prevention of further episodes of syncope in children.