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Cited by 105Cardiovascular Syncope and Autonomic DisordersHeart Rate Variability and Autonomic ControlVestibular and auditory disorders

Decreased upright cerebral blood flow and cerebral autoregulation in normocapnic postural tachycardia syndrome

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Ocon, Anthony J., Medow, Marvin S., Taneja, Indu, Clarke, Debbie, Stewart, Julian M.·2009·American Journal of Physiology-Heart and Circulatory Physiology
DOI 10.1152/ajpheart.00138.2009PMC PMC2724195
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Abstract

Postural tachycardia syndrome (POTS), a chronic form of orthostatic intolerance, has signs and symptoms of lightheadedness, loss of vision, headache, fatigue, and neurocognitive deficits consistent with reductions in cerebrovascular perfusion. We hypothesized that young, normocapnic POTS patients exhibit abnormal cerebral autoregulation (CA) that results in decreased static and dynamic cerebral blood flow (CBF) autoregulation. All subjects had continuous recordings of mean arterial pressure (MAP) and CBF velocity (CBFV) using transcranial Doppler sonography in both the supine supine position and during a 70° head-up tilt. During tilt, POTS patients ( n = 9) demonstrated a higher heart rate than controls ( n = 7) (109 ± 6 vs. 80 ± 2 beats/min, P < 0.05), whereas controls demonstrated a higher MAP than POTS (87 ± 2 vs. 77 ± 3 mmHg, P < 0.05). Also during tilt, mean CBFV decreased 19.5 ± 2.6% in POTS patients versus 10.3 ± 2.0% in controls ( P < 0.05). We then used a transfer function analysis of MAP and CFBV in the frequency domain to quantify these changes. The low-frequency (LF; 0.04–0.15 Hz) component of CBFV variability increased during tilt in POTS patients (supine: 3 ± 0.9 vs. tilt: 9 ± 2, P < 0.02). In POTS patients, there was an increase in LF and high-frequency coherence between MAP and CBFV, an increase in LF gain, and a lack of significant change in phase. Static CA may be less effective in POTS patients compared with controls, since immediately after tilt CBFV decreased more in POTS patients and was highly oscillatory and autoregulation did not restore CBFV to baseline values until the subjects became supine. Dynamic CA may be less effective in POTS patients because MAP and CBFV during tilt became almost perfectly synchronous. We conclude that dynamic and static autoregulation of CBF are less effective in POTS patients compared with control subjects during orthostatic challenge.

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  • POTS patients have significantly greater decreases in thoracic and cerebral blood flow when compared to healthy controls during tilt.

    “Other studies have also demonstrated that POTS patients have significantly greater decreases in thoracic and cerebral blood flow when compared to healthy controls during tilt (21, 23, 25-27).”

    From Postural orthostatic tachycardia syndrome: mechanisms and new therapies (2020) · cites this paper as [27]

  • Other studies found excessive reductions in middle cerebral artery blood velocity during head-up tilt in POTS, possibly due to sympathetic or hypocapnic cerebral vasoconstriction.

    “Others have shown excessive reductions in middle cerebral artery blood velocity measured by transcranial Doppler in POTS during HUTT, perhaps related to sympathetic-or hypocapnic-mediated cerebral vasoconstriction (Ocon et al., 2009;Medow et al., 2014;Del Pozzi et al., 2014;Jordan et al., 1998).”

    From Postural tachycardia syndrome – Diagnosis, physiology, and prognosis (2018) · cites this paper as Ocon et al., 2009

  • Ocon et al. observed lower cerebral blood flow and impaired autoregulation in POTS patients with normal carbon dioxide levels, which may argue against hyperventilation as the cause.

    “Possibly arguing against hyperventilation as the underlying cause, Ocon et al. showed reduced cerebral blood flow and autoregulation in normocapnic POTS patients (Ocon et al., 2009).”

    From Postural tachycardia syndrome – Diagnosis, physiology, and prognosis (2018) · cites this paper as Ocon et al., 2009

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Authors
Ocon, A. J., Medow, M. S., Taneja, I., Clarke, D., & Stewart, J. M.
Affiliations
New York Medical College (US)
ORCID
Venue
American Journal of Physiology-Heart and Circulatory Physiology
Publisher
American Physiological Society
Published
2009-08
Volume
297
Issue
2
Pages
H664-H673
ISSN
  • 0363-6135 (ISSN-L)
  • 1522-1539
DOI
10.1152/ajpheart.00138.2009
PMC
PMC2724195
OpenAlex
W2135620001
Cited by
105
References
63
Citations by year
2026: 5 · 2025: 7 · 2024: 5 · 2023: 4 · 2022: 3 · 2021: 5 · 2020: 7 · 2019: 5 · 2018: 6 · 2017: 3 · 2016: 6 · 2015: 12 · 2014: 11 · 2013: 6 · 2012: 6
FWCI
6.75
Type
journal article
Language
en
Open access
Locations
  • American Journal of Physiology-Heart and Circulatory Physiology (publishedVersion)
  • Europe PMC (PubMed Central) (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • American Heart Association
  • National Heart, Lung, and Blood Institute (5-R01-HL-074873-05, R01HL087803, 1-R01-HL-087803-01A1, R01HL074873, 1-R21-HL-091948-01, R21HL091948)
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, cerebral autoregulation, cerebral blood flow, orthostatic intolerance, head-up tilt, normocapnia, transfer function analysis, mean arterial pressure
MeSH terms
Adolescent, Adult, Blood Pressure, Carbon Dioxide, Cerebrovascular Circulation, Female, Heart Rate, Homeostasis, Humans, Male, Respiratory Mechanics, Supine Position, Ultrasonography, Doppler, Transcranial, Tilt-Table Test, Postural Orthostatic Tachycardia Syndrome, Young Adult

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