View clinical trials related to Orthostatic Intolerance.
Filter by:The goal of this clinical trial (pilot study) is to learn about the microcirculatory regulation of the lower extremity under orthostatic stress with and without RIC - Remote Ischemic Preconditioning in healthy participants. The main question it aims to answer are: Do the beneficial effects of RIC withstand orthostatic stress? / Does RIC benefit lower extremity microcirculation in ortho-statically stressed subjects? Is there a relationship/correlation between the variables of microcirculation and hemodynamics in the context of RIC and orthostatic loading?
This study is aimed primarily at providing a simple and effective form of treatment to reduce the symptoms of Initial Orthostatic Hypotension (IOH) and prevent syncope. We will first characterize the physiology of IOH, and then we will study four sit-to-stand maneuvers, each with a different stress tests to identify the role of sympathetic activity vs. simple muscle contraction in IOH. Then we will complete an additional two sit-to-stands with interventions designed to decrease the blood pressure drop (and hopefully symptoms) with initial stand. These consist of physical counter maneuvers, which may be a possible treatment that can be used to mitigate the drop in blood pressure (BP) seen in IOH during a stand and relieve presyncope symptoms.
We and others have shown that many younger patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) have orthostatic intolerance (OI), i.e., they can't tolerate prolonged standing. OI in ME/CFS is often accompanied by either postural tachycardia syndrome (POTS) in which standing results in an excessive heart rate, and neurally mediated hypotension (NMH) in which standing causes a fall in blood pressure and fainting. Intravenous fluids can alleviate these symptoms, but is difficult to administer; oral fluids fail to provide the same benefit. We would therefore like to test the effectiveness of an oral rehydration solution (ORS, W.H.O. formula) making use of co-transport of glucose and sodium, to reverse these symptoms in ME/CFS subjects with POTS or NMS, and will compare these results with healthy control subjects.
The investigators will test whether an intravenous infusion of saline (salt water) will improve the exercise capacity in patients with 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.
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.
This trial is designed to study the effects of various mechanistically unique medications in controlling excessive increases in heart rate with standing and in improving the symptoms of orthostatic intolerance in patients with this disorder.