Tilt Table Testing in Paediatric Orthostatic Intolerance: Is 10 Min Long Enough?

Recent cardiovascular literature suggests that orthostatic testing protocols should be tailored according to diagnostic purpose, distinguishing syncope evaluation from assessment of autonomic dysfunction in chronic orthostatic intolerance (COI). In adults, autonomic testing is commonly interpreted within a 10-min observation period, such as the active stand test. However, no specific time-based protocol has been clearly established for paediatric groups. This study examined whether a 10-min head-up tilt table test (HUTT) provides sufficient diagnostic yield in paediatric COI.

We retrospectively screened 410 paediatric patients who underwent a 30-min, non-pharmacological HUTT between 2008 and 2024, of whom 97 were included in the final cohort after excluding syncope-only presentations and other underlying diseases. Positive responses were classified as orthostatic hypotension, postural orthostatic tachycardia syndrome or vasovagal syncope. Cumulative positivity rates were compared across 10-, 20- and 30-min intervals, and time to first positive response was analysed by COI subtype.

Cumulative positivity increased with longer testing, from 25.8% at 10 min to 44.3% at 20 min and 55.6% at 30 min. Median time to positivity was 14 min overall, occurring later in orthostatic hypotension and vasovagal syncope than in postural orthostatic tachycardia syndrome. A substantial proportion of positive responses occurred beyond the first 10 min.

In paediatric COI, a 10-min HUTT may be insufficient to detect diagnostically relevant haemodynamic responses. These findings suggest that future studies of paediatric COI may need to consider orthostatic testing protocols with a minimum duration of 20 min to optimise diagnostic yield.