Comparison between the fast and the traditional nitroglycerin head-up tilt test in paediatric population

The shortened protocol of Nitroglycerin (NTG)-potentiated head-up tilt testing (HUTT), the so-called "fast Italian protocol," has been shown to significantly reduce test duration while maintaining diagnostic yield and safety in adults with suspected reflex syncope. To date, no data is available in paediatric patients. Aim of the study was to compare the positivity rate of the Fast protocol with that of the Traditional protocol in children and adolescents.

We retrospectively analyzed 302 consecutive paediatric patients (mean age 14.4 ± 2.8 years; 46.7% male) who underwent HUTT for suspected reflex syncope at two paediatric syncope units. Patients were evaluated using either a traditional NTG-potentiated protocol (n = 149) or the Fast Italian protocol (n = 153), characterized by shorter passive and active phases. Haemodynamic responses were classified according to the VASIS classification.

HUTT was positive in 81.2% of patients undergoing the traditional protocol and in 73.2% of those undergoing the Fast protocol, with no significant difference between groups (p = 0.1). Compared with the Traditional, in the Fast protocol the positivity was lower during the passive phase (7.8% vs. 36.2%; p < 0.001) but higher during the NTG-potentiated phase (65.4% vs. 45%; p < 0.001). The overall distribution of haemodynamic response types was similar between protocols, with mixed responses being the most frequent, followed by cardioinhibitory and vasodepressive patterns.

In paediatric patients with suspected reflex syncope, the Fast Italian HUTT provides a diagnostic yield comparable to that of the traditional nitroglycerin-potentiated protocol. Shortening the protocol does not significantly affect the distribution of haemodynamic response types.