Autoimmune Basis for Postural Tachycardia Syndrome

Part of paid clinical trials in Oklahoma City, Oklahoma.

Sponsor
Vanderbilt University Medical Center
Study ID
NCT02725060
Status
Enrolling By Invitation

Conditions

  • Arrhythmias, Cardiac
  • Autonomic Nervous System Diseases
  • Cardiovascular Diseases
  • Orthostatic Intolerance
  • Postural Orthostatic Tachycardia Syndrome
  • Postural Tachycardia Syndrome
  • Primary Dysautonomias
  • Tachycardia

Eligibility Criteria

Sex
ALL
Age
18 Years - 50 Years
Healthy Volunteers
Accepted

Interventions

  • phenylephrine — DRUG
    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 — DRUG
    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.
  • 25 micro-Ci of radiation — RADIATION
    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.
  • Posture study with blood samples — PROCEDURE
    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.
  • 24-hour heart rhythm and blood pressure monitoring — PROCEDURE
    Blood pressure, heart rate and ECG monitoring for 24 hours
  • Quantitative Axonal Sudomotor Reflex Testing — PROCEDURE
    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.
  • Autonomic function tests — PROCEDURE
    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.
  • Rebreathing test — OTHER
    Cardiac output will be measured using the rebreathing technique (Innocor)
  • Assessment of splanchnic capacitance — OTHER
    Splanchnic capacitance will be assessed using cpap and body impedance to construct pressure volume curves
  • microneurography — PROCEDURE
    microneurography will be measured in the peroneal nerve to assess sympathetic activity.

Study Details

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.

Key Dates

Start date
Feb 29, 2016
Status verified
Nov 2025
Primary completion
Oct 31, 2026
Completion
Dec 31, 2026

Study Design

Enrollment
58 participants (estimated)
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
OTHER

Arms

  • Experimental: 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

Primary Outcome Measure

Autoantibody levels [ Time Frame: up to 10 minutes ]

Locations (2)

FacilityCityStateZIPSite coordinators
University of Oklahoma Health Sciences CenterOklahoma CityOklahoma73117-1213-
Autonomic Dysfunction CenterNashvilleTennessee37232-

Find similar trials in Oklahoma City, OK

By research site
University of Oklahoma Health Sciences Center· Oklahoma City, OKAutonomic Dysfunction Center· Nashville, TN

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