View clinical trials related to Orthostatic Intolerance.
Filter by:The purpose of Lunar OI (Orthostatic Intolerance) is to determine if there are differences between males and females in tolerance to and cardiovascular responses during different angles of head-up tilt simulating gravity levels less than or equal to Earth's gravity. Also, this study will determine if a gradient compression garment affects tolerance to tilting and the cardiovascular stress at different tilt angles. Males and females are being identified by biological sex. This will be a two-phased study design. In Phase I we will determine whether there are differences in the development of signs or symptoms of orthostatic intolerance between males and females when tilted head up on a table to different angles to simulate gravity levels that astronauts may experience when landing on or launching from the surface of the Moon. In Phase II, the tilt tests simulating the same gravity levels from Phase I will be repeated, but a custom-made lower-body compression garment will be worn to see if wearing the garment affects the development of orthostatic intolerance. For both study phases, before tilting, a drug will be administered to reduce the amount fluid in the blood (plasma) to levels similar to that experienced by astronauts during spaceflight.
Observational two phase, retrospective and prospective registry study to assess the prevalence of and characterize outcomes of autonomic dysfunction (AD) in patients who undergo bariatric surgery (BS) and to better define the underlying pathophysiology of AD following BS.
This is a pilot dose-finding study to test the hypothesis that mirabegron increases systolic blood pressure (BP), prevents syncope/presyncope, and improves the quality of life (QOL), functional capacity, chest pain, and overactive bladder (OAB) symptoms in patients with postural orthostatic tachycardia syndrome (POTS) who have a documented history of hypotension inadequately responsive to conventional treatments. The American Heart Association funds this study.
The investigators are interested in whether discrete counterpressure maneuvers, or muscle movements in the lower body, will boost blood pressure and cardiovascular control in children who faint. We will record cardiovascular responses to maneuvers of exaggerated sway, leg crossing, crouching, and gluteal muscle tensing in children who faint (N=20), as well as their height, weight, muscularity, and pubertal (Tanner) stage. Autonomic cardiovascular control will be measured using a Valsalva manoeuvre (expiration against a closed airway for 20 seconds) and a supine-stand test. The primary outcomes are noninvasive measures of cardiovascular responses to the maneuvers (blood pressure, cerebral blood flow, and stroke volume (volume of blood pumped per heartbeat). Comparisons will be made across levels of sex, diagnosis, Tanner stage, muscularity, height, and degree of autonomic control.
The investigators will assess the efficacy of clinically recommended counterpressure maneuvers (CPM) in preventing syncope for paediatric patients. Participants presenting to the emergency department (ED) will first provide written informed consent. In stage I, they will be asked to complete a brief survey documenting the presentation of their syncopal episode, and any prodromal symptoms they experienced. Participants that consent to the second stage of the study will either receive usual care (control arm) or training in counter pressure maneuvers alongside usual care (intervention arm; leg crossing, bending, arm tensing). These patients will be followed for one years time, and will be asked to complete monthly surveys detailing their syncopal and presyncopal recurrence. Medical records will be accessed over the duration of the study to identify any changes in medical diagnosis.
Incidence of orthostatic intolerance and orthostatic hypotension after intravenous administration of morphine in patients prior to hip or knee arthroplasty.
Incidence and pathophysiologic hemodynamics of postoperative orthostatic intolerance and orthostatic hypotension in patients receiving antihypertensives
Postural Orthostatic Tachycardia Syndrome (POTS) is characterized by symptoms of chronic orthostatic intolerance such as fatigue, lightheadedness, dizziness, palpitations and by pronounced tachycardia upon standing. The aims of the present research study are to test whether a daily transcutaneous vagal nerve stimulation (tVNS) performed for 14 consecutive days may improve heart rate response and reduce disabling symptoms while standing.
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
Incidence and pathophysiologic hemodynamics of orthostatic intolerance and orthostatic hypotension in patients undergoing UKA