Aldosterone & Sodium Regulation in Postural Tachycardia Syndrome - Screening

NCT01783288 | Active Not Recruiting

• 2 other identifiers: IRB 121817R01HL102387
• Study Type: interventional
• Target: 110
• Locations: 1 country
• Sites: 1

Brief Summary

The purpose of the study is to determine whether patients meet criteria for Postural Tachycardia Syndrome (or not) and have reduced blood volume (or not). Both of these are important screening elements to Aim 3 of a National Institutes of Health Grant. The purposes of Aim 3 are to determine 1. whether a high dietary sodium level appropriately expands plasma volume in Postural Orthostatic Tachycardia, 2. whether plasma renin activity and aldosterone are modified appropriately by changes in dietary sodium in Postural Tachycardia Syndrome and 3. whether patients with Postural Tachycardia Syndrome have improvements in their orthostatic tachycardia and symptoms as a result of a high dietary sodium level.

Conditions

Postural Tachycardia Syndrome

Keywords

Postural tachycardia syndrome; orthostatic intolerance; orthostatic tachycardia; POTS

Outcome Measures

Primary Outcomes (1)

• blood volume deviation (%) from individual predicted volumes

  Compare blood volume deviations using the 131-I-Albumin method. Deviations will be reported as a percentage deviation from an individual's predicted value. These values will be compared between POTS patients and healthy control groups.

  2 days

Study Arms (1)

All participants

OTHER

All participants will be administered all procedures as described previously. Interventions: Autonomic Function Testing, Posture Study ,Measurement of Total Blood Volume ,Exercise Capacity Test

Other: Autonomic Function Testing; Other: Posture Study; Procedure: Measurement of Total Blood Volume; Other: Exercise Capacity Test

Interventions

Autonomic Function Testing OTHER

heart rate and blood pressure will be continuously monitored while participants undergo a variety of breathing techniques (deep breathing, rapid breathing, blowing against resistance) and during sustained handgrip and cold pressor (hand in ice water). All tests are meant to stimulate the autonomic nervous system to produce changes in blood pressure and heart rate of short duration that reflect how well the autonomic nervous system is functioning. Also during autonomic function testing, cardiac output will be measured to analyze the shift of fluids in the body (body impedance) and / or by analyzing the air that is breathed.

All participants

Posture Study OTHER

Blood pressure, heart rate and blood samples (for catecholamines and hormones) will be measured \& collected in the supine (lying) and upright position for each participant.

Also known as: Supine & standing blood pressure, heart rate & blood draws.

All participants

Measurement of Total Blood Volume PROCEDURE

Total blood volume is measured by using iodinated I-131 tagged human serum albumin.

Also known as: blood sample at baseline and at 12 minutes, I-131 is administered.

All participants

Exercise Capacity Test OTHER

Participants will ride on a stationary recumbent bicycle and the resistance will be gradually increased while expired air is measured.

Also known as: Masimal Oxygen Consumption Test

All participants

Eligibility Criteria

• Age: 18 Years - 50 Years
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Age between 18-50 years old
• Patients with suspected POTS and healthy volunteers
• Sedentary healthy subjects of similar age and gender than patients will also be recruited.
• Only female participants are eligible.
• Able and willing to provide informed consent

You may not qualify if:

• Smokers
• Overt cause for postural tachycardia, i.e., acute dehydration
• Significant cardiovascular, pulmonary, hepatic, or hematological disease by history or prior testing
• Highly trained athletes
• Subjects with somatization or severe anxiety symptoms will be excluded
• Pregnant (positive pregnancy test) or breastfeeding
• Hypertension defined as supine resting BP\>145/95 mmHg off medications or needing antihypertensive medication
• Other factors which in the investigator's opinion would prevent the participant from completing the protocol, including poor compliance during previous studies or an unpredictable schedule
• Unable to give informed consent

Sponsors & Collaborators

• Vanderbilt University: lead
• National Heart, Lung, and Blood Institute (NHLBI): collaborator
• National Institutes of Health (NIH): collaborator

Study Sites (1)

Vanderbilt University Medical Center

Nashville, Tennessee, 37232, United States

Location

MeSH Terms

Conditions

Postural Orthostatic Tachycardia Syndrome; Orthostatic Intolerance

Interventions

Supine Position; Heart Rate; Blood Specimen Collection

Condition Hierarchy (Ancestors)

Primary Dysautonomias; Autonomic Nervous System Diseases; Nervous System Diseases; Neurologic Manifestations; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Posture; Musculoskeletal Physiological Phenomena; Musculoskeletal and Neural Physiological Phenomena; Vital Signs; Physical Examination; Diagnostic Techniques and Procedures; Diagnosis; Hemodynamics; Cardiovascular Physiological Phenomena; Circulatory and Respiratory Physiological Phenomena; Specimen Handling; Clinical Laboratory Techniques; Punctures; Surgical Procedures, Operative; Investigative Techniques

Study Officials

• Alfredo J Gamboa, MD

  Vanderbilt University Medical Center

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: SCREENING
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Research Associate Professor of Medicine

Study Record Dates

• First Submitted: January 25, 2013
• First Posted: February 4, 2013
• Study Start: February 1, 2013
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): December 1, 2026
• Last Updated: January 13, 2026

Record last verified: 2026-01

Locations

US (1)