ArticleHypertension (Dallas, Tex. : 1979)2014
Reduced cerebral blood flow with orthostasis precedes hypocapnic hyperpnea, sympathetic activation, and postural tachycardia syndrome.
Article in Hypertension (Dallas, Tex. : 1979), 2014. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT04271878 (Hypercapnia and Orthostatic Tolerance in Postural Orthostatic Tachycardia Syndrome), which is not on this map. Cited by 29 papers, 2 of them syntheses that pooled it.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Hypercapnia and Orthostatic Tolerance in Postural Orthostatic Tachycardia Syndrome
Who cites it
29 citing papers in PubMed, 2 syntheses or guidelines pooled it, 47 citations in OpenAlex.
- Mapping cerebral blood flow in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and orthostatic intolerance: insights from a systematic review.Journal of translational medicine · 2025Pooled it
- Is there a relationship between hypocapnia and tachycardia in postural orthostatic tachycardia syndrome (POTS)? A systematic review.Clinical autonomic research : official journal of the Clinical Autonomic Research Society · 2023Pooled it
- Impact of hypocapnia and cerebral perfusion on orthostatic tolerance.The Journal of physiology · 2014Trial
- Utility and best practices for clinical diagnostic testing of the autonomic nervous system: A Consensus Statement Endorsed by the American Autonomic Society and the American Association of Neuromuscular & Electrodiagnostic Medicine.Clinical autonomic research : official journal of the Clinical Autonomic Research Society · 2026Review
- Assessment of internal consistency reliability and concurrent validity of PROMISJournal of patient-reported outcomes · 2026Article
- Clinical and Immunovirological Characteristics Associated with Cardiovascular Dysautonomia in Long COVID.Journal of clinical medicine · 2026Article
- Stroke volume reduction impairs cerebrovascular regulation through ETCOClinical autonomic research : official journal of the Clinical Autonomic Research Society · 2026Article
- N95 masks increase brain blood velocity and parasympathetic outflow, yet worsen orthostatic symptoms in a healthy cohort.Physiological reports · 2025Article
- Cerebral Blood Flow in Orthostatic Intolerance.Journal of the American Heart Association · 2025Review
- Hyperventilation during rest and exercise in orthostatic intolerance and Spiky-Leaky Syndrome.Frontiers in neurology · 2025Article
- Effect of Positional Changes on Cerebral Perfusion in Parkinson's Disease Patients With Orthostatic Hypotension.Journal of movement disorders · 2024Article
- Novel Mechanisms of Postural Hyperventilation in Postural Orthostatic Tachycardia Syndrome: Toward Discovery of Terra Incognita.JACC. Basic to translational science · 2024Article
- Reduced Stroke Volume and Brain Perfusion Drive Postural Hyperventilation in Postural Orthostatic Tachycardia Syndrome.JACC. Basic to translational science · 2024Article
- Is it time to move beyond blood pressure and heart rate during head-up tilt testing?Clinical autonomic research : official journal of the Clinical Autonomic Research Society · 2024Article
- Anticipatory central command on standing decreases cerebral blood velocity causing hypocapnia in hyperpneic postural tachycardia syndrome.Journal of applied physiology (Bethesda, Md. : 1985) · 2023Article
- Carotid Artery Revascularization Improves Cardiac Sympathetic Nerve Activity in Patients With Carotid Artery Stenosis.Cardiology research · 2022Article
- Long-Term COVID 19 Sequelae in Adolescents: the Overlap with Orthostatic Intolerance and ME/CFS.Current pediatrics reports · 2022Review
- The preponderance of initial orthostatic hypotension in postural tachycardia syndrome.Journal of applied physiology (Bethesda, Md. : 1985) · 2020Article
- Heart Rate Variability in Head-Up Tilt Tests in Adolescent Postural Tachycardia Syndrome Patients.Frontiers in neuroscience · 2020Article
- Intermittent Calf Compression Delays the Onset of Presyncope in Young Healthy Individuals.Frontiers in physiology · 2019Article
Corrections and comments
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Authors and funding
5 authors at 1 institution in 1 country.
Funding
Abstract
Hyperventilation and reduced cerebral blood flow velocity can occur in postural tachycardia syndrome (POTS). We studied orthostatically intolerant patients, with suspected POTS, with a chief complaint of upright dyspnea. On the basis of our observations of an immediate reduction of cerebral blood flow velocity with orthostasis, we hypothesize that the resulting ischemic hypoxia of the carotid body causes chemoreflex activation, hypocapnic hyperpnea, sympathetic activation, and increased heart rate and blood pressure in this subset of POTS. We compared 11 dyspneic POTS subjects with 10 healthy controls during a 70° head-up tilt. In POTS subjects during initial orthostasis before blood pressure recovery; central blood volume and mean arterial pressure were reduced (P<0.025), resulting in a significant (P<0.001) decrease in cerebral blood flow velocity, which temporally preceded (17±6 s; P<0.025) a progressive increase in minute ventilation and decrease in end tidal CO2 (P<0.05) when compared with controls. Sympathoexcitation, measured by muscle sympathetic nerve activity, was increased in POTS (P<0.01) and inversely proportional to end tidal CO2 and resulted in an increase in heart rate (P<0.001), total peripheral resistance (P<0.025), and a decrease in cardiac output (P<0.025). The decrease in cerebral blood flow velocity and mean arterial pressure during initial orthostasis was greater (P<0.025) in POTS. Our data suggest that exaggerated initial central hypovolemia during initial orthostatic hypotension in POTS results in reduced cerebral blood flow velocity and postural hypocapnic hyperpnea that perpetuates cerebral ischemia. We hypothesize that sustained hypocapnia and cerebral ischemia produce sympathoexcitation, tachycardia, and a statistically significant increase in blood pressure.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.