Orthostatic Intolerance, Orthostatic Tachycardia, Postural Tachycardia Syndrome
Conditions
Keywords
saline, sodium, kidney, tachycardia
Brief summary
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.
Detailed description
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.
Interventions
OTHERnormal saline (0.9%)
liter normal saline over 30 minutes x 1 dose
Sponsors
National Center for Research Resources (NCRR)
National Heart, Lung, and Blood Institute (NHLBI)
Vanderbilt University
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
DIAGNOSTIC
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Urinary Na excretion | 24h and then hourly post saline load |
Secondary
| Measure | Time frame |
|---|---|
| Catecholamine levels | 1 day |
Countries
United States
Outcome results
None listed