Cited by 330Cardiovascular Syncope and Autonomic DisordersHeart Rate Variability and Autonomic ControlCardiovascular and exercise physiology

Cardiac origins of the postural orthostatic tachycardia syndrome

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Fu, Qi, VanGundy, Tiffany B., Galbreath, M. Melyn, Shibata, Shigeki, Jain, Manish, Hastings, Jeffrey L., Bhella, Paul S., Levine, Benjamin D.·2010·Journal of the American College of Cardiology

Abstract

Objectives To test the hypothesis that a small heart coupled with reduced blood volume contributes to the Postural Tachycardia Syndrome (POTS), while exercise training improves this syndrome. Background Patients with POTS have marked increases in heart rate during orthostasis. However, the underlying mechanisms are unknown and the effective therapy is uncertain. Methods Twenty-seven POTS patients underwent autonomic function tests, cardiac MRI, and blood volume measurements. Twenty-five of them participated in a 3-mo specially designed exercise training program with 19 completing the program; these patients were reevaluated after training. Results were compared with those of 16 healthy controls. Results Upright heart rate and total peripheral resistance were greater, while stroke volume and cardiac output were smaller in patients than controls. Baroreflex function was similar between groups. Left ventricular mass (median [25%, 75%], 1.26 [1.12, 1.37] vs 1.45 [1.34, 1.57] g/kg; P<0.01) and blood volume (60 [54, 64] vs 71 [65, 78] ml/kg; P<0.01) were smaller in patients than controls. Exercise training increased left ventricular mass and blood volume by ~12% and ~7%, and decreased upright heart rate by 9 [1, 17] bpm. Ten out of 19 patients no longer met POTS criteria after training, while patients’ Quality of Life assessed by Short-Form 36 was improved in all patients after training. Conclusions Autonomic function was intact in POTS patients. The marked tachycardia during orthostasis was attributable to a small heart coupled with reduced blood volume. Exercise training improved or even cured this syndrome in the majority of patients. It seems reasonable to offer POTS a new name based on its underlying pathophysiology – “The Grinch Syndrome”, because in this famous children’s book by Dr. Seuss, the main character had a heart that was “two sizes too small.”

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Crossref · 10.1016/j.jacc.2010.02.043

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  • Deconditioned POTS patients have reduced left ventricular mass, stroke volume, and blood volume, and these improve with exercise training.

    “Deconditioned patients with POTS have reduced left ventricular mass, stroke volume, and blood volume,35 which improve with exercise training.”

    From 2015 Heart Rhythm Society Expert Consensus Statement on the Diagnosis and Treatment of Postural Tachycardia Syndrome, Inappropriate Sinus Tachycardia, and Vasovagal Syncope (2015) · cites this paper as [35]

    The Discussion reports that patients with POTS had lower left ventricular mass and blood volume than sedentary controls, as well as smaller upright stroke volume. The Results report that exercise training increased left ventricular mass and blood volume, but do not establish that stroke volume also improved after training. (LLM, conf=0.84)

    Experimental — accuracy not yet measured
  • There is a tight relationship between stroke volume and HR in men, healthy women, and women with POTS.

    “Figure 2B shows the tight relationship between stroke volume and HR in men, healthy women, and women with POTS (4,12).”

    From Postural Orthostatic Tachycardia Syndrome (2019) · cites this paper as [4]

    The Discussion (page not provided) links smaller stroke volume to higher heart rate in POTS patients and describes a similar mechanism in young women. It does not establish a tight stroke-volume–heart-rate relationship across all three groups. The Methods (page not provided) report only one healthy male control, so the claim about men is not supported by this study. (LLM, conf=0.84)

    Experimental — accuracy not yet measured
  • Healthy women have smaller stroke volumes and higher HRs compared with healthy men, whereas women with POTS have both an exaggerated fall in stroke volume and an apparent compensatory rise in HR.

    “healthy women have smaller stroke volumes and higher HRs compared with healthy men, whereas women with POTS have both an exaggerated fall in stroke volume and an apparent compensatory rise in HR.”

    From Postural Orthostatic Tachycardia Syndrome (2019) · cites this paper as [4]

    The Discussion (page unavailable) reports smaller upright stroke volume and greater heart rate in POTS patients than in healthy controls, and describes the tachycardia as an apparent compensatory response. It also says healthy women have smaller hearts than men, but does not establish that healthy women have smaller stroke volumes and higher heart rates than men. Nor does it directly establish an exaggerated fall in stroke volume in the POTS patients studied, as distinct from a smaller upright stroke volume. (LLM, conf=0.86)

    Experimental — accuracy not yet measured
  • One feature that appears to be universally present in all POTS is cardiovascular deconditioning, characterized by cardiac atrophy and hypovolemia.

    “One feature that appears to be universally present in all POTS is cardiovascular deconditioning, a specific biological process characterized by cardiac atrophy and hypovolemia (4).”

    From Postural Orthostatic Tachycardia Syndrome (2019) · cites this paper as [4]

    The Discussion reports smaller left ventricular mass and lower blood volume in the patients studied, and describes deconditioning in terms of cardiac atrophy and hypovolemia. It does not establish that deconditioning is universally present in all people with POTS; the Discussion instead says that almost all of its patients had a history of physical inactivity and notes that POTS may have heterogeneous mechanisms. Page numbers are unavailable in our copy. (LLM, conf=0.88)

    Experimental — accuracy not yet measured
  • Multiple parameters associated with deconditioning have been demonstrated in POTS patients, including reduced cardiac size and mass (by 16%), reduced blood volume (by 20%), reduced stroke volume, and reduced peak oxygen uptake (VO2 peak) when compared with matched sedentary controls.

    “Multiple parameters associated with deconditioning have also been demonstrated in POTS patients, including reduced cardiac size and mass (by 16%), reduced blood volume (by 20%), reduced stroke volume, and reduced peak oxygen uptake (VO 2 peak) when compared with matched sedentary controls (4).”

    From Postural Orthostatic Tachycardia Syndrome (2019) · cites this paper as [4]

    The Discussion (POTS and “deconditioning”; page unavailable) reports approximately 16% lower left ventricular mass, 20% lower blood and plasma volume, and markedly smaller upright stroke volume in POTS patients than in healthy sedentary controls. The Results (Exercise training effects; page unavailable) show that peak oxygen uptake increased after training in POTS patients, but do not establish that it was lower than in controls. The 16% figure applies specifically to left ventricular mass, not cardiac size as well. (LLM, conf=0.87)

    Experimental — accuracy not yet measured

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Research works printed but not linked: 1

  1. [51]Fu Q Shook RP Shibata S Vasomotor sympathetic and hemodynamic responses during upright tilt in the Postural Orthostatic Tachycardia Syndrome The FASEB Journal 2007 21 750.20

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Authors
Fu, Q., VanGundy, T. B., Galbreath, M. M., Shibata, S., Jain, M., Hastings, J. L., Bhella, P. S., & Levine, B. D.
Affiliations
Texas Health Dallas (US)
Corresponding author
Levine, Benjamin D.
Venue
Journal of the American College of Cardiology
Publisher
Elsevier BV
Published
2010-06
Volume
55
Issue
25
Pages
2858-2868
ISSN
0735-1097 (ISSN-L)
OpenAlex
W2130006990
Cited by
329
References
62
Citations by year
2026: 18 · 2025: 24 · 2024: 30 · 2023: 23 · 2022: 26 · 2021: 26 · 2020: 31 · 2019: 16 · 2018: 19 · 2017: 18 · 2016: 19 · 2015: 14 · 2014: 16 · 2013: 9 · 2012: 18
FWCI
16.18
Type
journal article
Language
en
Open access
Locations
  • Journal of the American College of Cardiology (publishedVersion)
  • PubMed (publishedVersion)
  • Europe PMC (PubMed Central) (acceptedVersion)
  • PubMed Central (acceptedVersion)
Funders
  • National Institutes of Health (HL075283)
  • National Space Biomedical Research Institute (CA00701)
  • Clinical and Translational Research Center(formerly the General Clinical Research Center (RR00633)
Topics
  • Health Sciences › Medicine › Surgery › Cardiovascular Syncope and Autonomic Disorders
  • Health Sciences › Medicine › Cardiology and Cardiovascular Medicine › Heart Rate Variability and Autonomic Control
  • Health Sciences › Medicine › Complementary and alternative medicine › Cardiovascular and exercise physiology
Keywords
postural orthostatic tachycardia syndrome, cardiac output, stroke volume, blood volume, left ventricular mass, exercise training, orthostatic tachycardia, autonomic function, baroreflex, systemic vascular resistance, quality of life
MeSH terms
Adult, Blood Pressure Determination, Blood Volume, Electrocardiography, Postural Balance, Female, Follow-Up Studies, Heart Diseases, Heart Rate, Hemodynamics, Humans, Magnetic Resonance Imaging, Male, Probability, Reference Values, Severity of Illness Index, Exercise, Case-Control Studies, Treatment Outcome, Risk Assessment, Tilt-Table Test, Statistics, Nonparametric, Postural Orthostatic Tachycardia Syndrome, Young Adult

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