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Pathophysiology of Orthostatic Intolerance

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ClinicalTrials.gov Identifier: NCT00608725
Recruitment Status : Recruiting
First Posted : February 6, 2008
Last Update Posted : September 15, 2022
Sponsor:
Collaborator:
National Institutes of Health (NIH)
Information provided by (Responsible Party):
Satish R. Raj, Vanderbilt University Medical Center

Study Description
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Brief Summary:
The purpose of this study is to describe the mechanism of orthostatic intolerance, relying on cardiovascular physiological studies. The syndrome is of undetermined etiology, but the syndrome causes impairment of a number of young adults, females more than males, with symptoms of tachycardia, fatigue, lightheadedness, palpitations, blurred vision, chest discomfort, difficulty concentrating, and dizziness with the upright posture. It is believed that many different pathophysiological processes can give rise to this disorder.

Condition or disease Intervention/treatment Phase
Tachycardia Postural Orthostatic Tachycardia Syndrome Radiation: DAXOR Procedure: QSweat Drug: Intrinsic Heart Rate Not Applicable

Study Design
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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 100 participants
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Diagnostic
Official Title: Pathophysiology of Orthostatic Intolerance
Study Start Date : December 1996
Estimated Primary Completion Date : December 2025
Estimated Study Completion Date : December 2025
Arms and Interventions
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Arm Intervention/treatment
Patients
Patients with orthostatic intolerance
 Radiation: DAXOR
131-I-Human Serum Albumin Blood Volume Assessment Kit
Other Name: Volumex

Procedure: QSweat
Quantitative Sweat Testing
Other Names:
  • QSART
  • Quantitative Axonal Sudomotor Reflex Testing

Drug: Intrinsic Heart Rate
Atropine 0.04 mg/kg IV in divided doses Propranolol 0.2 mg/kg IV in divided doses
Other Names:
  • Inderal
  • IHR
Healthy Control Subjects
Healthy subjects to determine "normal" response
 Radiation: DAXOR
131-I-Human Serum Albumin Blood Volume Assessment Kit
Other Name: Volumex

Procedure: QSweat
Quantitative Sweat Testing
Other Names:
  • QSART
  • Quantitative Axonal Sudomotor Reflex Testing

Drug: Intrinsic Heart Rate
Atropine 0.04 mg/kg IV in divided doses Propranolol 0.2 mg/kg IV in divided doses
Other Names:
  • Inderal
  • IHR


Outcome Measures
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Primary Outcome Measures :
  1. Physiological abnormalities in orthostatic intolerance [ Time Frame: 1 day ]

Secondary Outcome Measures :
  1. blood volume [ Time Frame: 1 day ]
  2. intrinsic heart rate [ Time Frame: 1 hour ]
  3. quantitative sweat testing [ Time Frame: 2 hours ]
  4. residual sympathetic function after pharmacological autonomic blockade [ Time Frame: 3 hours ]
  5. norepinephrine spillover [ Time Frame: 3 hours ]

Eligibility Criteria
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Ages Eligible for Study:   18 Years to 80 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Orthostatic intolerance

Exclusion Criteria:

  • Inability or unwillingness to give informed consent
Contacts and Locations
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Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00608725


Contacts
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Contact: Bonnie K Black, BSN CNP 615-343-6499 rajlab@vumc.org

Locations
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United States, Tennessee
Vanderbilt University Recruiting
Nashville, Tennessee, United States, 37232
Principal Investigator: David Robertson, M.D.         
Sub-Investigator: Italo Biaggioni, MD         
Sub-Investigator: Satish R Raj, MD MSCI         
Sponsors and Collaborators
Satish R. Raj
National Institutes of Health (NIH)
Investigators
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Principal Investigator: David Robertson, MD Vanderbilt University
More Information
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Additional Information:

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):

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Responsible Party: Satish R. Raj, Assistant Professor of Medicine & Pharmacology, Vanderbilt University Medical Center
ClinicalTrials.gov Identifier: NCT00608725    
Other Study ID Numbers: 8398
NIH HL56693
First Posted: February 6, 2008    Key Record Dates
Last Update Posted: September 15, 2022
Last Verified: September 2022
Keywords provided by Satish R. Raj, Vanderbilt University Medical Center:
heart rate
blood pressure
blood volume
sympathetic nervous system
 orthostatic tachycardia
orthostatic intolerance
POTS
Additional relevant MeSH terms:
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Orthostatic Intolerance
Postural Orthostatic Tachycardia Syndrome
Tachycardia
Arrhythmias, Cardiac
Heart Diseases
Cardiovascular Diseases
Cardiac Conduction System Disease
Pathologic Processes
Primary Dysautonomias
Autonomic Nervous System Diseases
Nervous System Diseases
 Neurologic Manifestations
Propranolol
Adrenergic beta-Antagonists
Adrenergic Antagonists
Adrenergic Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Physiological Effects of Drugs
Anti-Arrhythmia Agents
Antihypertensive Agents
Vasodilator Agents