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Autoimmun basis for posturalt takykardisyndrom

5. november 2026 opdateret af: Luis E Okamoto, Vanderbilt University Medical Center

The purpose of this study is to see if some people with postural tachycardia syndrome (POTS) have higher levels of immune proteins (autoantibodies) directed against receptors of the autonomic nervous system, and if these autoantibodies make a difference in their POTS symptoms. The investigators also want to see if the levels of these autoantibodies stay the same over time.

Studieoversigt

Status

Aktiv, ikke rekrutterende

Betingelser

Intervention / Behandling

Detaljeret beskrivelse

Postural tachycardia syndrome (POTS) is a debilitating disorder resulting from cardiovascular autonomic dysfunction, has many causes and is very difficult to treat effectively. The investigators have identified the presence of autoantibodies (immune proteins) directed against some receptors of the autonomic nervous system that can cause patient's symptoms on standing.

The present study is designed to test the hypothesis that patients with POTS harbor functional autoantibodies to adrenergic receptors that lead to an excessive tachycardia characteristic of POTS. For this purpose, this study will define the prevalence, burden, and the in vivo physiological significance of these adrenergic antibodies in a well-phenotyped and representative cohort of patients with POTS and a matched cohort of healthy control subjects, and will characterize the stability of these autoantibodies over time in affected POTS patients.

Undersøgelsestype

Interventionel

Tilmelding (Anslået)

58

Fase

  • Ikke anvendelig

Kontakter og lokationer

Dette afsnit indeholder kontaktoplysninger for dem, der udfører undersøgelsen, og oplysninger om, hvor denne undersøgelse udføres.

Studiesteder

    • Oklahoma
      • Oklahoma City, Oklahoma, Forenede Stater, 73117-1213
        • University of Oklahoma Health Sciences Center
    • Tennessee
      • Nashville, Tennessee, Forenede Stater, 37232
        • Autonomic Dysfunction Center

Deltagelseskriterier

Forskere leder efter personer, der passer til en bestemt beskrivelse, kaldet berettigelseskriterier. Nogle eksempler på disse kriterier er en persons generelle helbredstilstand eller tidligere behandlinger.

Berettigelseskriterier

Aldre berettiget til at studere

18 år til 50 år (Voksen)

Tager imod sunde frivillige

Ja

Køn, der er berettiget til at studere

Alle

Beskrivelse

Inclusion Criteria:

  • 18-50 years old
  • Postural Tachycardia Syndrome: Heart rate increase >30 bpm from supine within 10 min of standing, in the absence of orthostatic hypotension (>20/10 mmHg fall in blood pressure), with chronic symptoms (> 6 months), and in the absence of other acute cause of orthostatic tachycardia.
  • Able and willing to provide informed consent
  • Female premenopausal subjects must utilize adequate birth control and willingness to undergo serum beta-hCG testing
  • The subject must understand and be able to comply with the study procedures and restrictions.

Exclusion Criteria:

  • Hypertension (>150 mmHg systolic and >100 mmHg diastolic) based on history or findings at screening.
  • Orthostatic hypotension (consistent drop in blood pressure >20/10 mmHg with 10 min stand)
  • Pregnancy
  • Cardiovascular disease, such as myocardial infarction within 6 months, angina pectoris, significant arrhythmia (sinus tachycardia is not excluded), deep vein thrombosis, pulmonary embolism
  • History of serious neurologic disease
  • History or presence of significant immunological or hematological disorders
  • Clinically significant gastrointestinal impairment that could interfere with dietary compliance or drug absorption
  • Impaired hepatic function (aspartate amino transaminase and/or alanine amino transaminase >1.5 x upper limit of normal range)
  • Impaired renal function (serum creatinine >1.5 mg/dL)
  • Hematocrit <28%
  • Current or concurrent disease that could affect the absorption, action or disposition of the drug, or clinical or laboratory assessments.
  • Any underlying or acute disease requiring regular medication that could possibly pose a threat to the subject or make implementation of the protocol or interpretation of the study results difficult
  • Inability to comply with the protocol

Healthy control subjects will be healthy, non-smoking and on no chronic medications at the time of the study. Healthy control subjects will be group-matched to the POTS patients for age and gender. We will attempt to study female patients in the first half of their menstrual cycle to minimize cyclical variability.

Studieplan

Dette afsnit indeholder detaljer om studieplanen, herunder hvordan undersøgelsen er designet, og hvad undersøgelsen måler.

Hvordan er undersøgelsen tilrettelagt?

Design detaljer

  • Primært formål: Andet
  • Tildeling: N/A
  • Interventionel model: Enkelt gruppeopgave
  • Maskning: Ingen (Åben etiket)

Våben og indgreb

Deltagergruppe / Arm
Intervention / Behandling
Eksperimentel: Autonomic and Antibody Assessments

On up to 3 study days, POTS patients and control subjects will have several tests to assess autonomic function and to detect the presence of autoantibodies to adrenergic receptors. The following tests will de done but in some participants it may not be necessary to do all of them. The investigator will discuss with each participant which particular tests will be done in each particular case:

  • Posture study with blood samples for autoantibody testing
  • 24-hour heart rhythm and blood pressure monitoring
  • autonomic function tests
  • Quantitative Axonal Sudomotor Reflex Testing
  • Total blood volume assessment
  • Pharmacologic testing with phenylephrine
  • Pharmacologic testing with isoproterenol
  • Cardiac output with rebreathing
  • Assessment of splanchnic capacitance
  • Microneurography

Phenylephrine is a selective α1-adrenergic receptor agonist. It will be given in IV bolus injections starting from 12.5 ug. Incremental doses will be given every ~3 min up to 800 ug or until systolic blood pressure increases by 25 mmHg

Isoproterenol is non-selective beta-adrenergic agonist. It will be given in IV bolus injections starting from 0.025 ug. Incremental doses will be given every ~3 min until heart rate increases by 25 bpm. This intervention is optional.

Andre navne:
  • isoprenalin
  • isuprel

Using injection of iodinated I-131 tagged human serum albumin nominally 25 micro-Ci of radiation, blood samples are drawn before and 30 minutes after injection.

Andre navne:
  • DAXOR

Blood pressure and heart rate will be measured while supine and then while standing for up to 30 minutes. Blood will be drawn in each position to measure hormones that regulate blood pressure and blood volume. An additional sample will be collected in the supine position for the autoantibody assessment.

Andre navne:
  • ortostatisk udfordring
  • ortostatisk stresstest

Blood pressure, heart rate and ECG monitoring for 24 hours

Andre navne:
  • 24 Holter

The QSART assesses the ability of sympathetic nerve terminals in the skin to release acetylcholine and increase sweat production. The test is performed at 4 sites over the forearm, proximal lateral leg, medial distal leg and proximal foot.

Andre navne:
  • QSART
  • svedtest

The autonomic function tests will determine how well the autonomic nervous system regulates blood pressure and heart rate. These tests include breathing deeply for two minutes, breathing fast for 30 seconds, maintaining a handgrip for 3 minutes, breathing against pressure for 15 seconds, and placing the hand in ice water for 1 minute. In addition, participants will be tilted up on a tilt table for up to 10 minutes while recording their heart rate, blood pressure and cardiac output.

Cardiac output will be measured using the rebreathing technique (Innocor)

Andre navne:
  • måling af hjertevolumen

Splanchnic capacitance will be assessed using cpap and body impedance to construct pressure volume curves

microneurography will be measured in the peroneal nerve to assess sympathetic activity.

Andre navne:
  • msna

Hvad måler undersøgelsen?

Primære resultatmål

Resultatmål
Foranstaltningsbeskrivelse
Tidsramme
Blodtryk efter phenylephrin bolus
Tidsramme: 1-2 minutter efter bolusinjektioner
1-2 minutter efter bolusinjektioner
Hjertefrekvens efter isoproterenol bolus
Tidsramme: 1-2 minutter efter bolusinjektioner
1-2 minutter efter bolusinjektioner
Autoantibody levels
Tidsramme: up to 10 minutes

Blood samples collected while supine during the posture study will be analyzed for autoantibody positivity in POTS patients and control subjects.

up to 10 minutes
Orthostatic change in heart rate
Tidsramme: up to 10 minutes

Difference between standing and supine heart rates.

up to 10 minutes

Sekundære resultatmål

Resultatmål
Tidsramme
Blodtryksrespons under fase IV af Valsalva-manøvren
Tidsramme: op til 10 minutter
op til 10 minutter
Hørefrekvensrespons under fase IV af Valsalva-manøvren
Tidsramme: op til 10 minutter
op til 10 minutter

Samarbejdspartnere og efterforskere

Det er her, du vil finde personer og organisationer, der er involveret i denne undersøgelse.

Sponsor

Samarbejdspartnere

Efterforskere

  • Ledende efterforsker: Luis Okamoto, MD, Vanderbilt University Medical Center

Datoer for undersøgelser

Disse datoer sporer fremskridtene for indsendelser af undersøgelsesrekord og resumeresultater til ClinicalTrials.gov. Studieregistreringer og rapporterede resultater gennemgås af National Library of Medicine (NLM) for at sikre, at de opfylder specifikke kvalitetskontrolstandarder, før de offentliggøres på den offentlige hjemmeside.

Studer store datoer

Studiestart (Faktiske)

1. februar 2016

Primær færdiggørelse (Anslået)

1. februar 2027

Studieafslutning (Anslået)

1. juni 2027

Datoer for studieregistrering

Først indsendt

22. februar 2016

Først indsendt, der opfyldte QC-kriterier

30. marts 2016

Først opslået (Anslået)

31. marts 2016

Opdateringer af undersøgelsesjournaler

Sidste opdatering sendt (Faktiske)

10. november 2026

Sidste opdatering indsendt, der opfyldte kvalitetskontrolkriterier

5. november 2026

Sidst verificeret

1. november 2026

Mere information

Disse oplysninger blev hentet direkte fra webstedet clinicaltrials.gov uden ændringer. Hvis du har nogen anmodninger om at ændre, fjerne eller opdatere dine undersøgelsesoplysninger, bedes du kontakte register@clinicaltrials.gov. Så snart en ændring er implementeret på clinicaltrials.gov, vil denne også blive opdateret automatisk på vores hjemmeside .