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Cited by 13Cardiovascular Syncope and Autonomic DisordersHeart Rate Variability and Autonomic ControlVestibular and auditory disorders

Physiological and clinical comparison of active stand and head-up tilt tests in Postural Orthostatic Tachycardia Syndrome (POTS)

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Uppal, Jaiden, Baker, Jacquie R., Hira, Rashmin, Karalasingham, Kavithra, Ranada, Shaun, Deol, Paras, Sheldon, Robert S., Raj, Satish R.·2025·Autonomic Neuroscience
DOI 10.1016/j.autneu.2025.103281
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Abstract

Head-up tilt (HUT) and active stand tests (AST) are used in the diagnosis of Postural Orthostatic Tachycardia Syndrome (POTS), but their relative diagnostic accuracy is unclear. This necessitates a direct comparison under standardized conditions. We aimed to compare the hemodynamic responses and diagnostic accuracy of AST vs. HUT in POTS. To address this, patients with POTS ( n = 60) completed a 10-min AST followed by HUT on the same day. Beat-to-beat hemodynamics were recorded during 10-min supine baselines and each test. Delta values were calculated for each test (upright 1-min averages minus baseline average). Δ[heart rate] increased significantly over time (1_Min: 28 bpm to 10_Min: 40 bpm; P Time < 0.001), and was greater for HUT (33 bpm vs. 37 bpm; P ASTvHUT = 0.01), with significant Time x Condition interaction (38 bpm vs. 42 bpm at10min; P INT < 0.001). Δ[stroke volume] declined over time (1_Min: -18 ml to 10_Min: -32 ml); P Time < 0.001), with no significant test or interaction effects (P ASTvHUT = 0.36; P INT = 0.21). Δ[SBP] decreased (1_Min: −0.3 mmHg to 10_Min: −5.7 mmHg); P Time < 0.001) over time, with no test or interaction effects. Fewer patients met POTS heart rate criteria during the AST (AST: 74 % vs. HUT: 98 %; p < 0.001). Lowering the threshold to 27 bpm for AST narrowed the gap but was still significantly higher for HUT (AST: 83 % vs HUT: 98 %; p = 0.02). Orthostatic tachycardia differs between AST and HUT in patients with POTS. The proportion of patients with POTS meeting the heart rate diagnostic criteria differs significantly between AST and HUT, a discrepancy that can be mitigated by lowering the heart rate threshold for the AST.

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Authors
Uppal, J., Baker, J. R., Hira, R., Karalasingham, K., Ranada, S., Deol, P., Sheldon, R. S., & Raj, S. R.
Affiliations
University of Calgary (CA)
Corresponding author
Raj, Satish R.
ORCID
Venue
Autonomic Neuroscience
Publisher
Elsevier BV
Published
2025-08
Volume
260
Pages
103281
ISSN
1566-0702 (ISSN-L)
DOI
10.1016/j.autneu.2025.103281
OpenAlex
W4409590050
Cited by
13
References
39
Citations by year
2026: 12 · 2025: 1
FWCI
12.32
Type
journal article
Language
en
Open access
Licence
Locations
  • Autonomic Neuroscience (publishedVersion, cc-by-nc)
  • PubMed (publishedVersion)
Funders
  • Canadian Institutes of Health Research Clinical Trials Fund (MOP142426)
  • National Institutes of Health (UL1-TR000445)
  • Canadian Institutes of Health Research
  • Vanderbilt Institute for Clinical and Translational Research
Topics
  • Health Sciences › Medicine › Surgery › Cardiovascular Syncope and Autonomic Disorders
  • Health Sciences › Medicine › Cardiology and Cardiovascular Medicine › Heart Rate Variability and Autonomic Control
  • Life Sciences › Neuroscience › Neurology › Vestibular and auditory disorders
Keywords
postural orthostatic tachycardia syndrome, head-up tilt, diagnostic accuracy, orthostatic tachycardia, heart rate threshold, hemodynamic response, stroke volume, blood pressure, autonomic dysfunction
MeSH terms
Standing Position, Adult, Female, Heart Rate, Hemodynamics, Humans, Male, Middle Aged, Tilt-Table Test, Postural Orthostatic Tachycardia Syndrome, Young Adult

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