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OpenTrials
Active, Not Recruiting

NCT Number: NCT00581633

Acute Salt Handling in Orthostatic Intolerance

The investigators will test the hypothesis that patients with chronic orthostatic intolerance or postural orthostatic tachycardia syndrome (OI or POTS) will be unable to conserve urinary sodium as compared to healthy control subjects.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

Key information

Conditions

Postural Tachycardia Syndrome Arrhythmias, Cardiac Autonomic Nervous System Diseases Cardiac Conduction System Disease Cardiovascular Diseases Heart Diseases Nervous System Diseases Neurologic Manifestations Orthostatic Intolerance Orthostatic Tachycardia Pathologic Processes Pathological Conditions, Signs and Symptoms Postural Orthostatic Tachycardia Syndrome Primary Dysautonomias Signs and Symptoms Tachycardia

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Vanderbilt University

Nashville, Tennessee, 37232, United States

About this study

Patients with chronic OI appear to be hypovolemic with abnormalities in hormones that regulate salt & water handling. Increases in dietary salt have salutary effects on orthostatic tolerance in a physiological laboratory. The infusion of intravenous saline acutely decreased heart rate in this patient population. Preliminary data from Vanderbilt suggests abnormal salt handling in patients with chronic OI in a few patients. These data need to be confirmed and a better understanding of sodium handling in response to acute salt loads is required in these patients.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Diagnosed with orthostatic intolerance by Vanderbilt Autonomic Dysfunction Center (or healthy control subject)

Exclusion criteria

  • Overt or acute cause for orthostatic tachycardia
  • Hypertension (BP>145/95 or need for anti-hypertensive medications)
  • QRS duration > 120 msec on EKG
  • Pregnancy

Treatment and study plan

normal saline (0.9%)

Other

liter normal saline over 30 minutes x 1 dose

Primary outcomes

  1. Urinary Na excretion

    Time frame: 24h and then hourly post saline load

Secondary outcomes

  1. Catecholamine levels

    Time frame: 1 day

Sponsors and collaborators

Lead sponsor

Vanderbilt University

Other

Collaborators

  • National Center for Research Resources (NCRR)
  • National Heart, Lung, and Blood Institute (NHLBI)

Registry information

Official study title

Acute Renal Salt Handling in Orthostatic Intolerance

Important dates

Study start
2007
Primary completion
2029
Study completion
2029
First posted
Dec 27, 2007
Registry last updated
Oct 6, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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