Assessment of Vascular Endothelial Function in Postural Tachycardia Syndrome

Vanderbilt University Medical Center26 enrolled

Overview

The purpose of this study is to see if people with Postural Tachycardia Syndrome (POTS) have different levels of certain chemicals in their blood than people who don't have POTS. This study will test whether the blood vessels of people with POTS will react differently to certain tests than people without POTS. The hypothesis of the study is: Patients with POTS will have vascular endothelial dysfunction compared with control subjects.

Study Type

OBSERVATIONAL

Enrollment

Conditions

Postural Tachycardia Syndrome

Interventions

Blood Pressure and Blood FlowDEVICE

A blood pressure cuff will be placed on one arm and small probes on one finger on both hands. The probes also measure blood pressure. After 10 minutes, the arm blood pressure cuff will be inflated. The cuff will stay inflated for 5 minutes, then the air will be let out. A cuff will be place above the left calf and the left knee. The subject will lie quietly for 9 minutes, then blood pressure and calf blood flow will be measured for one minute. the lower leg cuff will be inflated after 1 minute, then the cuff will be deflated. The blood pressure and forearm blood flow will be recorded. Next, the cuff on the upper leg will be inflated for 5 minutes then, it will be released and the measurements of blood pressure and calf blood flow will be repeated. The study lasts about 2 hours.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 60 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: ALL: * Ages between 18-60 years old * Male and female subjects are eligible * Able and willing to give informed consent Additional criteria for POTS: * Diagnosed with postural tachycardia syndrome by the Vanderbilt Autonomic - Dysfunction Center (1. increase in heart rate \>/= 30 beats/minute with position change from supine to standing for 10 minutes and/or 2. Chronic symptoms consistent with POTS that are worse when upright and get better with recumbence. Additional criteria for Control subjects: * Healthy, non-obese, non-smokers without orthostatic tachycardia * Selected to match profiles of POTS patients (gender, age) * Not using vasoactive medications Exclusion Criteria: * Overt cause for postural tachycardia (such as acute dehydration) * Inability to give, or withdraw informed consent * Pregnancy * Other factors in the investigator's opinion would prevent the subject from completing the study

Locations (2)

Vanderbilt University Medical Center

Nashville, Tennessee, United States

Vanderbilt University

Nashville, Tennessee, United States

Outcomes

Primary Outcomes

RH-PAT index

The primary analysis of RH-PAT will involve a non-parametric, Mann Whitney U test of RH-PAT between POTS patients and Control subjects.

Time frame: The study will be complete in approximately 2 hours. There is no follow-up to this study.

Data from ClinicalTrials.gov

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