Autoimmune Basis for Postural Tachycardia Syndrome
Postural Orthostatic Tachycardia Syndrome, Postural Tachycardia Syndrome, Tachycardia
About this trial
This is an interventional other trial for Postural Orthostatic Tachycardia Syndrome focused on measuring POTS, Orthostatic Intolerance, Orthostatic Tachycardia
Eligibility Criteria
Inclusion Criteria:
- 18-50 years old
- Postural Tachycardia Syndrome: Heart rate increase >30 bpm from supine within 10 min of standing, in the absence of orthostatic hypotension (>20/10 mmHg fall in blood pressure), with chronic symptoms (> 6 months), and in the absence of other acute cause of orthostatic tachycardia.
- Able and willing to provide informed consent
- Female premenopausal subjects must utilize adequate birth control and willingness to undergo serum beta-hCG testing
- The subject must understand and be able to comply with the study procedures and restrictions.
Exclusion Criteria:
- Hypertension (>150 mmHg systolic and >100 mmHg diastolic) based on history or findings at screening.
- Orthostatic hypotension (consistent drop in blood pressure >20/10 mmHg with 10 min stand)
- Pregnancy
- Cardiovascular disease, such as myocardial infarction within 6 months, angina pectoris, significant arrhythmia (sinus tachycardia is not excluded), deep vein thrombosis, pulmonary embolism
- History of serious neurologic disease
- History or presence of significant immunological or hematological disorders
- Clinically significant gastrointestinal impairment that could interfere with dietary compliance or drug absorption
- Impaired hepatic function (aspartate amino transaminase and/or alanine amino transaminase >1.5 x upper limit of normal range)
- Impaired renal function (serum creatinine >1.5 mg/dL)
- Hematocrit <28%
- Current or concurrent disease that could affect the absorption, action or disposition of the drug, or clinical or laboratory assessments.
- Any underlying or acute disease requiring regular medication that could possibly pose a threat to the subject or make implementation of the protocol or interpretation of the study results difficult
- Inability to comply with the protocol
Healthy control subjects will be healthy, non-smoking and on no chronic medications at the time of the study. Healthy control subjects will be group-matched to the POTS patients for age and gender. We will attempt to study female patients in the first half of their menstrual cycle to minimize cyclical variability.
Sites / Locations
- University of Oklahoma Health Sciences Center
- Autonomic Dysfunction Center
Arms of the Study
Arm 1
Experimental
Autonomic and Antibody Assessments
On up to 3 study days, POTS patients and control subjects will have several tests to assess autonomic function and to detect the presence of autoantibodies to adrenergic receptors. The following tests will de done but in some participants it may not be necessary to do all of them. The investigator will discuss with each participant which particular tests will be done in each particular case: Posture study with blood samples for autoantibody testing 24-hour heart rhythm and blood pressure monitoring autonomic function tests Quantitative Axonal Sudomotor Reflex Testing Total blood volume assessment Pharmacologic testing with phenylephrine Pharmacologic testing with isoproterenol Cardiac output with rebreathing Assessment of splanchnic capacitance Microneurography