View clinical trials related to Postural Tachycardia Syndrome.
Filter by:Patients with POTS experience significant gastrointestinal symptoms. Current evidence suggesting that abnormal post-ganglionic sympathetic function could play a role in the pathophysiology of these GI abnormalities. Sympathetic fiber regulate motor and the postprandial GI peptides secretion. The focus of the present proposal is to determine glucose homeostasis, GI motility, and their association with GI and cardiovascular symptoms in POTS patients versus healthy controls. Furthermore, we will determine differences in these outcomes in POTS patients with and without evidence of postganglionic sympathetic fiber neuropathy. As a long-term goal, this study can lead us to understand the pathophysiology of common co-morbidities in patients with POTS to provide new treatment approaches and prevention strategies.
The Postural Tachycardia-Syndrome (POTS) is a form of autonomic dysregulation, typically accompanied by symptoms of orthostatic intolerance (OI). OI is defined by the inability to tolerate the upright position and is improved by lying down. POTS is considered a syndrome that may include a number of several disorders. Symptoms should be persistent for at least 6 months to reach a diagnosis. It is characterized by a sustained heart rate (HR) increment of 30 beats/min or more within 10 min of standing or head-up tilt (HUT) in adults, in the absence of orthostatic hypotension and with the presence of symptoms of OI. In children and adolescents a diagnosis requests a HR increment of at least 40 beats/min. The increment in HR when moving to an upright posture is often a response to a reduction in venous return, causing excessive blood pooling in the lower limbs. The symptoms present in POTS vary greatly. Typical symptoms are lightheadedness, dizziness, blurred vision, mental clouding ("brain fog") or cognitive dysfunction. Other symptoms may present as palpitations or chest pain. Additional symptoms consist of postural headaches, nausea, sleep disturbances, fatigue and gastrointestinal dysfunction. The manifestation of symptoms in POTS varies in severity, frequency and combination, resulting in POTS being a very heterogenous and subjective disorder. Symptoms can be severe and often make simple daily activities difficult to an extent that compromises the patients quality of life. Typically symptoms exacerbate in the mornings, after physical activity, after eating and during menstruation. This study objective is to examine the occurrence, mechanisms and causes of impaired attention in POTS as well as to test the effect of acute water ingestion for attention in POTS. The investigators therefore conduct a study including patients with POTS and healthy volunteers. All participants will receive a dossier of five self-assessment questionnaires after giving informed consent. Clinical examination includes 2 HUT-tests while standing for 15 minutes, conventional measuring of blood pressure, continuous recording of NIRS signals during testing, determination of pupil size, the diameter of the optic nerve and Neuropsychological testing (Test of Attentional Performance, mobility version" (TAP-M), Go/NoGo Test, Divided Attention Test)
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.
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.
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.
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.
This study uses an Alizarin Red powder mixture to characterize the sweat distributions in youth during tilt table testing. Patients with a known orthostatic sweat response from a prior clinical tilt table test in the investigators laboratory will be recruited. The Alizarin Red powder will be applied to exposed skin, and quantitative sweat will be measured at the thigh. During tilt testing, serial photos will be taken once the sweat response occurs. Sweat distributions will be compared during syncope (orthostatic sweat), during periods of anxiety (emotional sweat), and in patients with POTS (with and without syncope).
Orthostatic intolerance refers to symptoms that occur with standing and improve or resolve with recumbency. Few studies have evaluated orthostatic intolerance symptoms by electroencephalography (EEG), and none of those studies have focused on the adolescent-aged patient. This study will compare EEG characteristics and sweat rate during head-upright tilt (HUT) testing among patients with postural tachycardia syndrome (POTS) and patients with syncope without POTS. Patients with POTS will also undergo a separate HUT with abdominal and lower extremity compression. The primary aim of this study is to characterize video EEG changes that correspond with orthostatic intolerance in youth during HUT testing. The investigators hypothesize that the clinical encephalopathy related to POTS and referred to as 'brain fog' will have an electrographic correlate. Secondary aims include (1) EEG comparisons of POTS symptoms with and without abdominal and lower extremity compression during HUT, (2) correlation between sweat rate and EEG changes during HUT, and (3) analysis of EEG characteristics that distinguish syncope with POTS from syncope without POTS. The investigators hypothesize that POTS patients have prolonged syncopal prodromes (compared to syncope patients without POTS) which are protective of syncope during daily activities.
Background: - The autonomic nervous system helps control things that happen automatically in the body, like blood pressure, heart rate, and digestion. When it doesn t work properly, it s called dysautonomia. Researchers want to learn more about dysautonomias and train doctors to learn how to better diagnose them. Objectives: - To allow people with autonomic disorders to be evaluated. - To help fellows in the NIH Autonomic Disorders fellowship program see a variety of diseases in their training. Eligibility: - People age 18 and older with dysautonomia; children over age 2 if they might benefit - Healthy adult volunteers Design: - Participants will have different procedures depending on their symptoms. They will have one or more visits. They will have some but not all of the tests below. - Participants will have a medical history and physical exam. They may be tested for problems thinking. They may complete a symptom questionnaire. They may have their temperature and blood pressure taken. - Participants may have an intravenous line placed. A needle will guide a thin plastic tube into an arm vein. - Participants may have blood drawn several times. They may give a urine sample. - Participants may have an electrocardiogram. - How much blood a participant s heart is pumping and/or how much blood is flowing through their arm may be measured. The total amount of blood in their bloodstream may be measured. - Participants may have their ability to sweat and/or sense of smell tested. - Breathing, bowel sounds, and/or body functions may be monitored. - Pupil size, response to environmental temperature changes, and/or breathing may be measured. - Participants may have a bladder ultrasound. - Small pieces of skin may be taken for study.
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.