The effects of gender and test protocol on the results of head-up tilt test in patients with vasovagal syncope

Background: Head-up tilt testing (HUTT) is a well-established method for the diagnosis of reflex syncope. Some controversies exist whether gender and HUTT protocol influence HUTT results. Aim: To analyse the results of HUTT in patients with syncope in relation to their gender and used protocol of HUTT. Methods: We retrospectively analysed data of 537 consecutive patients (313 women and 224 men), aged 13-79 years with history of neurally-mediated syncope referred to HUTT The cardiogenic and neurological aetiology of syncope was excluded in all patients based on previous examination. In 375 patients standard HUTT (STD HUTT), according to the Westminster protocol, was used. In 257 patients in whom STD HUTT was negative, HUTT was continued with pharmacological provocation using isoproterenol intravenous infusion - 114 patients (ISO HUTT) or sublingual nitroglycerin - 143 patients (NTG HUTT). In the remaining 162 patients HUTT was performed according to the Italian protocol (ITL HUTT). The HUTT results were classified according to the VASlS scale. Results: Female gender dominated, however, syncope was induced in a similar proportion of women and men (77.3 vs. 70.5%, NS). There were also no significant differences in the type of vasovagal response (VVR) to HUTT between women and men. Mixed type of VVR was the most frequent after isoproterenol provocation (ISO HUTT), whereas cardioinhibitory type of VVR was the most frequent after nitroglycerin provocation (NTG HUTT). Conclusions: There is no significant relationship between gender and the result of HUTT The type of VVR is related to HUTT protocol - cardioinhibitory response is more frequent following nitroglycerin administration in comparison to standard protocol and HUTT with isoproterenol provocation.