Abstract 4364752: Presumed POTS, proven otherwise: diagnostic value of autonomic testing

Background: Postural Orthostatic Tachycardia Syndrome (POTS) is characterized by exaggerated heart rate increase upon standing, often accompanied by disabling symptoms such as palpitations, lightheadedness, fatigue and ‘brain fog’. As awareness of POTS has grown, its diagnosis has become more frequent; however, symptom overlap with other conditions such as orthostatic hypotension, vasovagal syncope, long-COVID, and anxiety raises the possibility of overdiagnosis and misclassification. Objective: To assess the frequency with which comprehensive autonomic testing confirms the diagnosis in patients referred with a presumptive clinical diagnosis of POTS Methods: The study population comprised 36 patients with presumed clinical diagnoses of POTS who were referred for autonomic testing between 2023 and 2025. All patients underwent standardized autonomic evaluation including active stand (AS), tilt table testing, Valsalva maneuver, and respiratory sinus arrhythmia. Laboratory confirmation of POTS was established by a baseline heart rate (HR) >60 bpm, a HR increase ≥30 bpm (or ≥40 bpm in those <20 years) on orthostatic challenge without hypotension and ultimate HR >100 bpm within 10 minutes. Results: The cohort was predominantly female (94%) with a median age of 31 years [21–48]. Common presenting symptoms included lightheadedness (55%), palpitations (50%), syncope or near-syncope (30%), and fatigue (5%). Notably, 75% had documented anxiety or depression, 22% had Ehlers-Danlos Hypermobility syndrome, and 36% had prior COVID-19 infection. Autonomic testing confirmed a diagnosis of POTS in 11% (4/36) of patients. Normal autonomic testing was observed in 61% (22/36), and 27% (10/36) were reclassified with alternative diagnoses such as orthostatic hypotension or vasovagal syncope. The mean HR increase for POTS patients with AS was 34.33±25 bpm, the maximum HR achieved was 124±17 bpm, and the average orthostatic systolic blood pressure drop was 23±17 mmHg. Conclusion: In this cohort of patients referred for suspected POTS, only 11% met diagnostic criteria during autonomic testing, while the majority either had normal results or were reclassified with alternative autonomic conditions. These findings suggest that overdiagnosis of POTS is common in the referral population and highlight the role of formal autonomic testing to improve diagnostic accuracy. Testing may help prevent misdiagnosis, reduce unnecessary treatment, and support more precise assessment of prognosis.