28 September 2026
: Case report 
Coexisting Postural Orthostatic Tachycardia Syndrome on Autonomic Reflex Testing in Functional Neurologic Disorder
Unusual clinical course, Challenging differential diagnosis
Sushmita Das
AEF 1, Sri Rama Narayana Yerraballa AEF 1, Priyanka Shekhawat AEF 1*
DOI: 10.12659/AJCR.953323
Am J Case Rep 2026; 27:e953323
Figure 1 Continuous heart rate and blood pressure during head-up tilt table test. Heart rate increases from 95 beats/min at baseline to 144 beats/min within 10 minutes of upright posture without fall in blood pressure, consistent with postural orthostatic tachycardia syndrome (excessive orthostatic tachycardia defined as > 40 beats/min for ages 12–19 years) [17].