Pathophysiology of Orthostatic Intolerance

NCT ID: NCT00608725

Last Updated: 2025-10-08

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

ACTIVE_NOT_RECRUITING

Clinical Phase

NA

Total Enrollment

260 participants

Study Classification

INTERVENTIONAL

Study Start Date

1996-12-31

Study Completion Date

2029-12-31

Brief Summary

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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.

Detailed Description

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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.

This is not a clinical trial in the classical sense, but an omnibus protocol to allow for disntinct and personalized pathophysiological testing.

Conditions

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Tachycardia Postural Orthostatic Tachycardia Syndrome

Study Design

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Allocation Method

NON_RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

DIAGNOSTIC

Blinding Strategy

NONE

Study Groups

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Patients

Patients with orthostatic intolerance

Group Type OTHER

DAXOR

Intervention Type RADIATION

131-I-Human Serum Albumin Blood Volume Assessment Kit

QSweat

Intervention Type PROCEDURE

Quantitative Sweat Testing

Intrinsic Heart Rate

Intervention Type DRUG

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

Healthy Control Subjects

Healthy subjects to determine "normal" response

Group Type OTHER

DAXOR

Intervention Type RADIATION

131-I-Human Serum Albumin Blood Volume Assessment Kit

QSweat

Intervention Type PROCEDURE

Quantitative Sweat Testing

Intrinsic Heart Rate

Intervention Type DRUG

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

Interventions

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DAXOR

131-I-Human Serum Albumin Blood Volume Assessment Kit

Intervention Type RADIATION

QSweat

Quantitative Sweat Testing

Intervention Type PROCEDURE

Intrinsic Heart Rate

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

Intervention Type DRUG

Other Intervention Names

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Volumex QSART Quantitative Axonal Sudomotor Reflex Testing Inderal IHR

Eligibility Criteria

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Inclusion Criteria

* Orthostatic intolerance

Exclusion Criteria

* Inability or unwillingness to give informed consent
Minimum Eligible Age

18 Years

Maximum Eligible Age

80 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Satish R. Raj

OTHER

Sponsor Role lead

Responsible Party

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Satish R. Raj

Assistant Professor of Medicine & Pharmacology

Responsibility Role SPONSOR_INVESTIGATOR

Principal Investigators

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David Robertson, MD

Role: PRINCIPAL_INVESTIGATOR

Vanderbilt University

Locations

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Vanderbilt University

Nashville, Tennessee, United States

Site Status

Countries

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United States

References

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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.

Reference Type DERIVED
PMID: 21266211 (View on PubMed)

Related Links

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Other Identifiers

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8398

Identifier Type: -

Identifier Source: org_study_id

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