Clinical Research Directory

Autoimmune Basis for Postural Tachycardia Syndrome

The purpose of this study is to test the hypothesis that an antibody-mediated autoimmune reaction will cause symptoms of autonomic dysfunction in some patients with postural tachycardia syndrome (POTS). The investigators further hypothesize that electrical stimulation of the vagus nerve will improve POTS symptoms, autoimmunity and inflammation.

Autonomic Determinants of POTS - Pilot1

Postural tachycardia syndrome (POTS) is a relatively common condition affecting mostly otherwise healthy young women. It is the cause of significant disability and an impairment in quality of life. These patients have high heart rate and symptoms during standing. Many of these patients are disabled and have a poor quality of life. The sympathetic nerves are part of the nervous system that helps to maintain normal blood pressures and heart rates during activities of daily life. The purpose of this study is to determine the importance of sympathetic activation as a cause of orthostatic symptoms. The investigators will assess the effects of a blood pressure medication (Moxonidine) on the symptoms during standing. Moxonidine lowers sympathetic activity. The investigators believe patients with high resting sympathetic activity might benefit from Moxonidine. It might reduce high heart rate and improve symptoms during standing. This study should help clinicians and the growing population of patients with POTS gain a better understanding of this disorder and find more personalized treatment.

Autonomic Determinants of POTS - Pilot 2

Postural tachycardia syndrome (POTS) is a relatively common condition affecting mostly otherwise healthy young women. These patients have high heart rate and disabling symptoms during standing. Quality of life may be poor. The sympathetic nerves in the autonomic nervous system help to maintain normal blood pressures and heart rates during activities of daily life. The purpose of this study is to determine the importance of sympathetic activation as a cause of orthostatic symptoms. The investigators will assess the effects of a blood pressure medication (Moxonidine) on the symptoms during standing. Moxonidine lowers sympathetic activity. The investigators believe patients with high resting sympathetic activity might benefit from Moxonidine. It might reduce high heart rate and improve symptoms during standing. This study should help clinicians and the growing population of patients with POTS gain a better understanding of this disorder and find more personalized treatment.

A Study of Pyridostigmine in Postural Tachycardia Syndrome

This is a 3-day study comparing pyridostigmine versus placebo in the treatment of postural tachycardia syndrome (POTS). The researchers expect pyridostigmine to improve tachycardia and stabilize blood pressure.

Periaqueductal Gray-vagus Nerve Interface Malfunction Explain the Natural History With Its Numerous Co-morbidities?

This study is being conducted to see how people with Postural tachycardia syndrome (POTS) make sense of the things they see. The information may help doctors to learn more about how the different parts of people's brains communicate.

The Impact of Improved Vagal Function on Periaqueductal Gray Connectivity

This study is being to see if participating in breathing exercise training and practicing this training will help with Postural tachycardia syndrome (POTS). The information may help doctors to learn more about how the different parts of people's brains communicate.

Modafinil and Cognitive Function in POTS

A common complaint among patients with Postural Tachycardia Syndrome (POTS) is "brain fog" or difficulty concentrating. This problem is poorly understood. The purpose of this study is to better understand the cognitive dysfunction associated POTS, and to determine optimal treatment strategies for this condition. In this study, the investigators will test the hypothesis that acute administration of the psychostimulant drug modafinil can improve seated measures of cognitive function in patients with POTS.

Aldosterone & Sodium Regulation in Postural Tachycardia Syndrome - Screening

The purpose of the study is to determine whether patients meet criteria for Postural Tachycardia Syndrome (or not) and have reduced blood volume (or not). Both of these are important screening elements to Aim 3 of a National Institutes of Health Grant. The purposes of Aim 3 are to determine 1. whether a high dietary sodium level appropriately expands plasma volume in Postural Orthostatic Tachycardia, 2. whether plasma renin activity and aldosterone are modified appropriately by changes in dietary sodium in Postural Tachycardia Syndrome and 3. whether patients with Postural Tachycardia Syndrome have improvements in their orthostatic tachycardia and symptoms as a result of a high dietary sodium level.

Breathing Device in Postural Orthostatic Tachycardia Syndrome (POTS)

The investigators will test whether breathing through an inspiratory resistance device will improve the ability to be upright and decrease heart rate increases on standing in patients with postural tachycardia syndrome.

Autoimmune Basis for Postural Tachycardia Syndrome

The purpose of this study is to see if some people with postural tachycardia syndrome (POTS) have higher levels of immune proteins (autoantibodies) directed against receptors of the autonomic nervous system, and if these autoantibodies make a difference in their POTS symptoms. The investigators also want to see if the levels of these autoantibodies stay the same over time.

Inappropriate Sinus Tachycardia Registry

The primary objective of this registry is to capture real-world safety and performance data on AtriCure devices used to ablate cardiac tissue when treating Inappropriate Sinus Tachycardia (IST) or Postural Tachycardia Syndrome (POTS). This is a retrospective and prospective, multicenter, US/OUS, observational data registry.

Ultrasound Guided Stellate Ganglion Block in Postural Tachycardia Syndrome

This single-center study aims to evaluate both immediate and long-term outcomes of stellate ganglion block (SGB) in a cohort of rigorously phenotyped patients with Postural Tachycardia Syndrome (POTS). By assessing the effects of SGB, this study seeks to determine its viability as an intervention for symptom control in POTS.

POTS NET mRNA Functional Correlation With NET Activity

DNA Acetylation can be responsible for significant down-regulation of transcription of the Norepinephrine Transporter (NET). NET is an important clearance transporter that removes norepinephrine (NE) from sympathetic neuronal synapses. Very low levels of NET can "cause" Postural Tachycardia Syndrome (POTS) or make these patients more susceptible to certain medications. Quantified NET messenger RNA (mRNA) levels from a peripheral blood sample may be able to assess NET availability, which is simpler than older methods. This has not been validated against NET function. In this protocol, the investigators seek to assess whether these NET mRNA levels correlate with NET function. The investigators will assess the DHPG (NET dependent NE metabolite):NE ratio in POTS patients and control subjects from both plasma and urine samples.

Sleep Actigraphy in Postural Tachycardia Syndrome (POTS)

We propose to use actigraphy (measured by activity watches) as a tool to quantify sleep disturbances in patients with orthostatic intolerance compared with healthy control subjects. In this pilot study, we will test the null hypothesis (Ho) that there are no differences in the sleep quality between patients with orthostatic intolerance and healthy control subjects.

Intravenous (IV) Saline and Exercise in Postural Tachycardia Syndrome (POTS)

The investigators will test whether an intravenous infusion of saline (salt water) will improve the exercise capacity in patients with postural tachycardia syndrome (POTS).

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.

fMRI in Postural Tachycardia Syndrome

Postural tachycardia syndrome (POTS) is one of the most common forms of chronic orthostatic intolerance in the United States. This is a disabling disorder characterized by an excessive increase in heart rate upon standing that is accompanied by symptoms such as dizziness and fatigue. One of the most under appreciated and bothersome symptoms of POTS is impaired cognition or "brain fog," which occurs to a level that interferes with daily activities such as work and education. Despite this high impact, the reasons why POTS patients have problems with cognition are not well understood. This project will test the overall hypothesis that "brain fog" in POTS is related to increased activation of cognitive brain regions during mental tasks when compared with healthy subjects, and that this activation is exacerbated by in the presence of orthostatic stress.

Vagal Stimulation in POTS

The purpose of this study is to investigate how the electrical stimulation of a nerve in the skin of the earlobe (transcutaneous vagal nerve stimulation), alone or in combination with two medications (galantamine and pyridostigmine), affects the way the autonomic (involuntary) nervous system controls heart rhythm, symptoms on standing, and inflammatory markers in female patients with postural tachycardia syndrome (POTS). The study consists of 2 parts: a screening (1-2 study days), and 3 testing days. The study will take 5 days total and about 16 participants will be screened for the study. The investigators estimate 13 will be eligible to participate in all of the study days.

POTS Adrenergic Ab (CIHR Aims #1&2)

Objective: In this pilot study, we will test the hypothesis that patients with POTS (age 18-60 years) will have a higher percentage of functional antibodies to adrenergic receptors compared with control subjects without POTS.

Autonomic Small Fiber Neuropathy and Ehlers Danlos Syndromes - Prospective Study and Registry

We examine patients with different autonomic neuropathies and Ehlers Danlos syndromes compared to healthy controls at three different points over time (baseline, after 3 months and after 1.5 years) to gain knowledge about the course of this disease and understand its pathophysiology, with a focus on Small Fiber neuropathy. Moreover we will validate the german version of the Malmö POTS Score and establish an easy diagnostic scheme for patients in outpatient care.

Phenotyping Mitochondrial and Immune Dysfunction in POTS With Targeted Clinical Intervention.

The mechanisms underlying POTS are not well understood. Though heterogeneous in nature, patients often present with symptoms that include fatigue, orthostatic lightheadedness and tachycardia, "brain fog", shortness of breath, and sleep disruption. The central mediator that links observations in disease entities similar to POTS is energy use and balance driven by mitochondrial health. Mitochondrial dysfunction (i.e. respiration defects, reactive oxygen species (ROS) generation, and structural abnormalities) are hallmarks of currently defined syndromes that resemble POTS symptomatology. Many patients with POTS have underlying immune system dysfunction, which, when treated, may improve the patient's overall health. Though autoimmunity has been demonstrated in POTS, overall immune dysregulation may be broader and include immune cell exhaustion and persistent inflammatory cytokine responses. Immune dysfunction including cellular exhaustion and persistent inflammation has been linked to mitochondrial function. Therefore, we hypothesize that a unifying feature of POTS results from latent or continued mitochondrial/immune dysfunction which then impacts multi-organ energy imbalance and immune homeostasis. Understanding and targeting mitochondria utilizing established, novel, and directed approaches including time-restricted eating (TRE) will help to unravel common etiologies and help us to better diagnose, manage, and treat POTS.

Hypercapnia and Orthostatic Tolerance in Postural Orthostatic Tachycardia Syndrome

The mechanism behind postural orthostatic tachycardia syndrome (POTS) involves many causes including a sympathetic nervous system problem. Blood gases, like carbon dioxide (CO2), have an important effect on sympathetic activation. The purpose of this research study is to determine if higher CO2 levels have any effect in lowering heart rate and reducing POTS symptoms when upright/standing. The investigators are also searching for the ideal CO2 concentration to achieve the most effective response

Crossover Study of Propranolol vs Ivabradine in POTS

1.0 BACKGROUND Postural tachycardia syndrome (POTS) is a disorder of chronic orthostatic intolerance characterized by symptoms of palpitations, lightheadedness, chest discomfort, shortness of breath, blurred vision, and mental clouding. These symptoms occur during standing and are associated with a marked increase in heart rate (HR) in the absence of hypotension, which typically resolve when sitting or lying down. Most importantly, POTS is associated with a very poor quality of life and significant functional disability. POTS patients commonly experience mental clouding ("brain fog") even while lying down or seated, which poses significant limitations to daily activities . Unfortunately, there is a relative paucity in the literature assessing therapies for POTS patients. Given that excessive tachycardia on standing is a fundamental component of this syndrome, a handful of studies have evaluated medications that reduce HR. Ivabradine is newer drug that is a selective If channel blocker that reduces HR without affecting other cardiovascular functions. 2.0 RATIONALE / STUDY PURPOSE The investigators propose to compare the efficacy of propranolol and ivabradine on HR response to standing, and symptom burden in patients with POTS. 3.0 Study Design This will be a single-center double-blind placebo-controlled randomized crossover trial conducted in patients with POTS to compare effects of (1) oral ivabradine 5 mg bid plus placebo BID (to fill out a QID schedule); (2) oral propranolol 10 mg qid; and (3) oral placebo qid in POTS patients. After a baseline screening assessment following a washout period of 7 days, participants will be randomized to start with a 4-week course of either ivabradine, propranolol or placebo. The other two treatments will be given in separate 4-week courses with a 7-day washout period between phases, with each participant acting as his or her own control. At the end of each 4-week phase, participants will complete the symptom-rating and HRQOL questionnaires, and also undergo tilt table testing to assess the change in HR at 10 min with head up tilt. Participants will undergo POTS testing at baseline and at the end of each 4-week treatment course. This will involve a total of 4 separate study visits.