You should not be able to simply pass or fail a tilt table test. This paper defines a measurable subtype of OI in patients whose HR and BP look completely normal on standard testing.

Foundational for the CO₂ and perfusion conversation in OI testing, and the fact that it dates to 1998 tells you everything about how long this evidence has been ignored at the clinical level.

A review article that explains in plain, coherent logic why CO₂ monitoring belongs in modern orthostatic testing. Useful for making the case to a clinician.

Frames POTS and HYCH/OCHOS as overlapping rather than distinct, and makes a direct claim about what is actually driving the tachycardia in POTS patients.

An important counterweight. Not every case of orthostatic cerebral hypoperfusion is explained by hyperventilation and CO₂ dysregulation. Autoregulation itself can be impaired even in normocapnic POTS.