NCT00608725

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.

Trial Health

75
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
260

participants targeted

Target at P75+ for not_applicable

Timeline
42mo left

Started Dec 1996

Longer than P75 for not_applicable

Geographic Reach
1 country

1 active site

Status
active not recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Progress90%
Dec 1996Dec 2029

Study Start

First participant enrolled

December 1, 1996

Completed
11.1 years until next milestone

First Submitted

Initial submission to the registry

January 22, 2008

Completed
15 days until next milestone

First Posted

Study publicly available on registry

February 6, 2008

Completed
21.8 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

December 1, 2029

Expected
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

December 1, 2029

Last Updated

October 8, 2025

Status Verified

October 1, 2025

Enrollment Period

33 years

First QC Date

January 22, 2008

Last Update Submit

October 3, 2025

Conditions

TachycardiaPostural Orthostatic Tachycardia Syndrome

Keywords

heart rateblood pressureblood volumesympathetic nervous systemorthostatic tachycardiaorthostatic intolerancePOTS

Outcome Measures

Primary Outcomes (1)

  • Physiological abnormalities in orthostatic intolerance

    varied metrics used here

    1 day

Secondary Outcomes (5)

  • blood volume

    1 day

  • intrinsic heart rate

    1 hour

  • quantitative sweat testing

    2 hours

  • residual sympathetic function after pharmacological autonomic blockade

    3 hours

  • norepinephrine spillover

    3 hours

Study Arms (2)

Patients

OTHER

Patients with orthostatic intolerance

Radiation: DAXORProcedure: QSweatDrug: Intrinsic Heart Rate

Healthy Control Subjects

OTHER

Healthy subjects to determine "normal" response

Radiation: DAXORProcedure: QSweatDrug: Intrinsic Heart Rate

Interventions

DAXORRADIATION

131-I-Human Serum Albumin Blood Volume Assessment Kit

Also known as: Volumex
Healthy Control SubjectsPatients
QSweatPROCEDURE

Quantitative Sweat Testing

Also known as: QSART, Quantitative Axonal Sudomotor Reflex Testing
Healthy Control SubjectsPatients
Intrinsic Heart RateDRUG

Atropine 0.04 mg/kg IV in divided doses Propranolol 0.2 mg/kg IV in divided doses

Also known as: Inderal, IHR
Healthy Control SubjectsPatients

Eligibility Criteria

Age18 Years - 80 Years
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • Orthostatic intolerance

You may not qualify if:

  • Inability or unwillingness to give informed consent

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Vanderbilt University

Nashville, Tennessee, 37232, United States

Location

Related Publications (1)

  • Mustafa HI, Garland EM, Biaggioni I, Black BK, Dupont WD, Robertson D, Raj SR. Abnormalities of angiotensin regulation in postural tachycardia syndrome. Heart Rhythm. 2011 Mar;8(3):422-8. doi: 10.1016/j.hrthm.2010.11.009. Epub 2011 Jan 22.

    PMID: 21266211DERIVED

Related Links

MeSH Terms

Conditions

TachycardiaPostural Orthostatic Tachycardia SyndromeOrthostatic Intolerance

Interventions

Propranolol

Condition Hierarchy (Ancestors)

Arrhythmias, CardiacHeart DiseasesCardiovascular DiseasesCardiac Conduction System DiseasePathologic ProcessesPathological Conditions, Signs and SymptomsPrimary DysautonomiasAutonomic Nervous System DiseasesNervous System DiseasesNeurologic ManifestationsSigns and Symptoms

Intervention Hierarchy (Ancestors)

PhenoxypropanolaminesPropanolaminesAmino AlcoholsAlcoholsOrganic ChemicalsPropanolsAminesNaphthalenesPolycyclic Aromatic HydrocarbonsHydrocarbons, AromaticHydrocarbons, CyclicHydrocarbonsPolycyclic Compounds

Study Officials

  • David Robertson, MD

    Vanderbilt University

    PRINCIPAL INVESTIGATOR

Study Design

Study Type
interventional
Phase
not applicable
Allocation
NON RANDOMIZED
Masking
NONE
Purpose
DIAGNOSTIC
Intervention Model
PARALLEL
Sponsor Type
OTHER
Responsible Party
SPONSOR INVESTIGATOR
PI Title
Assistant Professor of Medicine & Pharmacology

Study Record Dates

First Submitted

January 22, 2008

First Posted

February 6, 2008

Study Start

December 1, 1996

Primary Completion (Estimated)

December 1, 2029

Study Completion (Estimated)

December 1, 2029

Last Updated

October 8, 2025

Record last verified: 2025-10

Locations

US(1)