Clinical Trial: Dietary Salt in Postural Tachycardia Syndrome
Study Status: Active, not recruiting
Recruit Status: Active, not recruiting
Study Type: Interventional
Official Title: Dietary Salt in Postural Tachycardia Syndrome
Brief Summary: Patients with POTS may not adequately expand their plasma volume in response to a high-sodium diet. Mechanisms involved in the regulation of plasma volume, such as the renin-angiotensin-aldosterone system and renal DA, may be impaired in POTS and may respond inappropriately to changes in dietary sodium.The purpose of this study is to determine (1) whether a high dietary sodium level appropriately expands plasma volume in POTS; (2) whether plasma renin activity and aldosterone are modified appropriately by changes in dietary sodium in POTS; and (3) whether patients with POTS have improvements in their orthostatic tachycardia and symptoms as a result of a high dietary sodium level.
Detailed Summary:
Study Day 1
- Start 150 mEq Na+/day diet (POTS patients as inpatients; healthy control subjects with CRC provided outpatient diet)
- Start a 24h urine collection (for Na+, K+, Cr, fractionated catecholamines)
- Blood work
- Blood volume - carbon monoxide rebreathing
Study Day 2
- Complete 24h urine
- Start STUDY DIET (10 mEq Na+/day or 300 mEq Na+/day in a random order) after 3 meals of 150 mEq Na+/day are complete; water ad lib
Study Day 3 - 5
- Continue STUDY DIET; water ad lib
- On Day 5, a 24 hr holter combined ECG monitor will be placed on the subjects.
Study Day 6
- Continue STUDY DIET; water ad lib
- Remove 24h Holter combined ECG monitor and BP monitor from subject
- Start a 24h urine collection (for Na+, K+, Cr, fractionated catecholamines)
- Complete questionnaires
- NPO after midnight for study next day
Study Day 7 (BIG DAY)
- Awaken early (~6am) to void (still collecting 24h urine)
- Patient returns to bed, IV catheter inserted
- Posture
Sponsor: Vanderbilt University
Current Primary Outcome: blood volume [ Time Frame: after 7 days of each dietary sodium level ]
DAXOR (131-I labelled albumin) blood volume assay
Original Primary Outcome: Same as current
Current Secondary Outcome: Magnitude of suppression of aldosterone (from low sodium to high sodium diets) and a reduction in orthostatic tachycardia and orthostatic symptoms in POTS patients with the high-sodium diet. [ Time Frame: after 7 days of each dietary sodium intervention ]
Whether plasma renin activity and aldosterone are modified appropriately by changes in dietary sodium in POTS & whether patients with POTS have improvements in their orthostatic tachycardia and symptoms as a result of a high dietary sodium level.
Original Secondary Outcome: Same as current
Information By: Vanderbilt University Medical Center
Dates:
Date Received: March 2, 2012
Date Started: March 2012
Date Completion: March 2018
Last Updated: April 3, 2017
Last Verified: April 2017