Official Title: “Pathophysiology of Orthostatic Intolerance”

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.

Study Type: Interventional

Study Design: Diagnostic, Non-Randomized, Open Label, Uncontrolled, Parallel Assignment

Study Primary Completion Date: December 2011

Intervention(s) in this Clinical Trial

• Radiation: DAXOR
  • 131-I-Human Serum Albumin Blood Volume Assessment Kit
• Procedure: QSweat
  • Quantitative Sweat Testing
• Drug: Intrinsic Heart Rate
  • Atropine 0.04 mg/kg IV in divided doses Propranolol 0.2 mg/kg IV in divided doses

Arms, Groups and Cohorts in this Clinical Trial

• Other: Patients
  • Patients with orthostatic intolerance
• Other: Healthy Control Subjects
  • Healthy subjects to determine "normal" response

Primary Measures

• Physiological abnormalities in orthostatic intolerance
  • Time Frame: 1 day
    Safety Issue?: No

Secondary Measures

• blood volume
  • Time Frame: 1 day
    Safety Issue?: No
• intrinsic heart rate
  • Time Frame: 1 hour
    Safety Issue?: No
• quantitative sweat testing
  • Time Frame: 2 hours
    Safety Issue?: No
• residual sympathetic function after pharmacological autonomic blockade
  • Time Frame: 3 hours
    Safety Issue?: No
• norepinephrine spillover
  • Time Frame: 3 hours
    Safety Issue?: No

Inclusion Criteria:

• Orthostatic intolerance

Exclusion Criteria:

• Inability or unwillingness to give informed consent

Gender Eligibility for this Clinical Trial: Both

Minimum Age for this Clinical Trial: 18 Years

Maximum Age for this Clinical Trial: 80 Years

Are Healthy Volunteers Accepted for this Clinical Trial?: Accepts Healthy Volunteers

Lead Sponsor: Vanderbilt University

Overall Clinical Trial Officials and Contacts

David Robertson, MD Principal Investigator Vanderbilt University  

Overall Contact: Bonnie K Black, BSN CNP 615-343-6499 adc.research@vanderbilt.edu

Information obtained from ClinicalTrials.gov on October 10, 2008

Link to the current ClinicalTrials.gov record. http://clinicaltrials.gov/show/NCT00608725

Study ID Number: 8398

ClinicalTrials.gov Identifier: NCT00608725

Health Authority: United States: Institutional Review Board

Website of the Vanderbilt Autonomic Dysfunction Center