Clinical Research Directory

Fainting Detection And Early Warning In Syncope Evaluation Study (ARISE)

To characterize the impact of orthostatic hypotension (OH) and Vasovagal syncope on signals measured using a wearable Holter monitor in the clinic and ambulatory setting. To evaluate the relationship of signals measured from the Holter monitor with reported symptom severity of orthostatic intolerance per standard data collection, analysis, and questionnaires.

Orthostatic And Postprandial Hypotension In Hospitalized Older Adults (HOPE65)

The goal of this observational study is to determine how often orthostatic hypotension and postprandial hypotension occur in adults aged 65 years and older who are hospitalized in internal medicine departments. Orthostatic hypotension is defined as an excessive drop in blood pressure after standing up from a lying or sitting position. Postprandial hypotension is an excessive drop in blood pressure that occurs after eating a meal. These conditions can increase the risk of falls, fainting, loss of independence, and other health problems in older adults. The main questions this study aims to answer are: * How common orthostatic hypotension and postprandial hypotension are in hospitalized adults aged 65 years and older. * Whether these conditions are associated with medication use, chronic diseases, and geriatric syndromes (such as frailty, cognitive impairment, and functional decline). Participants will: * have blood pressure measured while lying down and standing * have blood pressure measured after a meal * undergo a comprehensive geriatric assessment, including evaluation of functional status, cognitive function, frailty, mobility, and nutritional status * provide information about medications and medical history * be followed for up to 12 months to record outcomes such as falls, syncope, hospitalization, and death

Autonomic Regulation of Blood Pressure and Heart Rate During Orthostasis and Exercise in Healthy and Hypertensive Individuals

The goal of this observational study is to assess arterial stiffness and autonomic regulation of blood pressure and heart rate in healthy adults and people with arterial hypertension during orthostatic stress and graded physical exercise. The main objective is to analyze cardiovascular responses to exercise on a cycle ergometer in different subgroups of participants with hypertension. The study includes healthy young adults and older adults with hypertension. Participants undergo standardized assessments including orthostatic testing, graded exercise testing on a cycle ergometer, electrocardiography, and measurement of arterial stiffness parameters such as pulse wave velocity, as well as other vascular and hemodynamic parameters. The results of this study are expected to improve understanding of cardiovascular physiology and autonomic regulation in people with hypertension and may contribute to earlier recognition of autonomic dysfunction and improved clinical management.

Reduction in Splanchnic Capacitance Contributes to Sympathetically Dependent Hypertension in Autonomic

The purpose of this study is to learn more about the regulation of the veins of the abdomen by the autonomic (involuntary) nervous system, and how this may affect high blood pressure. Normally, the autonomic nervous system controls how much blood flows in the veins. In people with high blood pressure, however, the autonomic nervous system is changed. This change may affect the way blood flows in the veins of the abdomen which may play a role in their high blood pressure. About 32 participants will be screened for the study. The investigators estimate 16 will be eligible to participate in all of the study days.

Deciphering Preserved Autonomic Function After Spinal Cord Injury

This study looks to characterize gradients of dysfunction in the autonomic nervous system after spinal cord injury. The autonomic nervous system plays key roles in regulation of blood pressure, skin blood flow, and bladder health- all issues that individuals with spinal cord injury typically suffer. Focusing on blood pressure regulation, the most precise metric with broad clinical applicability, the investigators will perform laboratory-based tests to probe the body's ability to generate autonomic responses. For both individuals with spinal cord injury and uninjured controls, laboratory-based experiments will utilize multiple parallel recordings to identify how the autonomic nervous system is able to inhibit and activate signals. The investigators anticipate that those with autonomic dysfunction after spinal cord injury will exhibit abnormalities in these precise metrics. The investigators will further have research participants wear a smart watch that tracks skin electrical conductance, heart rate, and skin temperature, which can all provide clues as to the degree of autonomic dysfunction someone may suffer at home. The investigators will look to see if any substantial connections exist between different degrees of preserved autonomic function and secondary autonomic complications from spinal cord injury. In accomplishing this, the investigators hope to give scientists important insights to how the autonomic nervous system works after spinal cord injury and give physicians better tools to manage these secondary autonomic complications.

Hemodynamic Mechanisms of Abdominal Compression in the Treatment of Orthostatic Hypotension in Autonomic Failure

Compression garments have been shown to be effective in the treatment of orthostatic hypotension in autonomic failure patients. The purpose of this study is to determine the hemodynamic mechanisms by which abdominal compression (up to 40 mm Hg) improve the standing blood pressure and orthostatic tolerance in these patients, and to compare them with those of the standard of care midodrine. The investigators will test the hypothesis that abdominal compression will blunt the exaggerated fall in stroke volume and the increase in abdominal vascular volume during head up tilt.

Research, Development, and Application of Intelligent Diagnostic System for Orthostatic Hypotension

Orthostatic hypotension (OH) has a high incidence rate of 30%-50% in the elderly and populations with neurodegenerative diseases. The resulting cerebral hypoperfusion significantly increases the risk of cerebral ischemia, falls, and cognitive decline. Traditional OH diagnosis primarily relies on intermittent cuff blood pressure measurements, leading to low detection rates and an inability to provide scientifically effective OH classification. Furthermore, existing research often overlooks cerebral hemodynamic mechanisms, particularly the assessment of dynamic cerebral autoregulation (dCA), making it difficult to study the mechanisms behind OH and its associated symptoms. To address these issues, the research team has preliminarily developed an "Intelligent Diagnostic System for Orthostatic Hypotension". This system innovatively integrates synchronous and continuous monitoring of multiple parameters, including non-invasive beat-to-beat blood pressure, transcranial Doppler (TCD) cerebral blood flow velocity, and electrocardiogram (ECG). It also enables the quantitative assessment of dynamic cerebral autoregulation function. The project will collaborate with fifteen high-level clinical centers in China to collect data from 2000 patients with orthostatic hypotension. The aim is to establish and externally validate a risk stratification model for OH. By integrating multimodal clinical and hemodynamic data, the investigators intend to construct an automated, precise intelligent system for the classification, subtyping, and risk stratification of OH. This initiative will establish a standardized diagnostic and management pathway covering early screening, precise classification, early warning, and stratified intervention. The goal is to provide key technological support for enhancing the early identification and standardized management of OH, thereby reducing its associated disability and mortality rates.

Non-invasive Spinal Cord Stimulation for Recovery of Autonomic Function After Spinal Cord Injury

This study is a pilot clinical trial to explore the efficacy of transcutaneous spinal cord stimulation (TCSCS) (proof-of-concept) in mitigating crucial autonomic dysfunctions that impact the health-related quality of life of individuals with spinal cord injury (SCI).

Automated Abdominal Binder for Orthostatic Hypotension

The automated inflatable abdominal binder is an investigational device for the treatment of orthostatic hypotension (low blood pressure on standing) in patients with autonomic failure. The purpose of this study is to determine safety and effectiveness of the automated abdominal binder in improving orthostatic tolerance in these patients.

Effects of Midodrine and Droxidopa on Splanchnic Capacitance in Autonomic Failure

The purpose of this study is to learn more about the effects of midodrine and droxidopa, two medications used for the treatment of orthostatic hypotension (low blood pressure on standing), on the veins of the abdomen of patients with autonomic failure. The study will be conducted at Vanderbilt University Medical Center, and consists of 2 parts: a screening and 2 testing days. The total length of the study will be about 5 days. About 34 participants will be screened for the study.

Water and the Gastropressor Response - Diurnal Variability

We will test the null hypothesis that there is no diurnal (morning to afternoon)variability in the blood pressure response to the ingestion of water 16 oz.

Water and the Gastropressor Response - Tachyphylaxis

We are studying the effects of oral water ingestion in patients with orthostatic hypotension. In this study, we are testing the null hypothesis that the blood pressure increase with oral water ingestion will not be diminished if a full prior water dose is given a few hours earlier.

POLish Registry of CArdioneuroablation and CArdioneuromodulation

The multicentre observational study POL-CA involves a wide spectrum of patients with a history of syncopy. The study recruits patients with diagnosed vasovagal syndrome, cardioinhibitory carotid sinus syndrome, symptomatic sinus bradycardia or atrioventricular block, postural orthostatic tachycardia syndrome, orthostatic hypotension, and inappropriate sinus tachycardia syndrome. This is an observational, controlled study with retrospective, clinical data analysis of previously treated patients and the analysis of syncopal patients prospectively recruited into the study. The aim of the POL-CA registry is to create a platform for physicians to record treatment data for patients undergoing procedures that affect innervation or modify cardiovascular reflexes (cardioneuroablation, cardioneuromodulation) in order to provide a multicentre summary of population characteristics and treatment outcomes based on a standardized POL-CA questionnaire and methodology for various arrhythmias.

Spinal Cord Transcutaneous Stimulation Effect on Blood Pressure in Acute Spinal Cord Injury (SCI)

The goal of this clinical trial is to evaluate the effect of transcutaneous spinal cord stimulation on blood pressure in individuals with an acute spinal cord injury (within 30 days of injury). Blood pressure instability, specifically orthostatic hypotension (a drop in blood pressure when moving lying flat on your back to an upright position), appears early after the injury and often significantly interferes with participation in the critical rehabilitation time period. The main questions it aims to answer are: 1. Can optimal spinal stimulation increase blood pressure and resolve orthostatic symptoms (such as dizziness and nausea) when individuals undergo an orthostatic provocation (a sit-up test)? Optimal stimulation and sham stimulation (which is similar to a placebo treatment) will be compared. 2. What are the various spinal sites and stimulation parameters that can be used to increase and stabilize blood pressure to the normal range of 110-120 mmHg? Participants will undergo orthostatic tests (lying on a bed that starts out flat and then moved into an upright seated position by raising the head of bed by 90° and dropping the base of the bed by 90° from the knee) with optimal and sham stimulation, and their blood pressure measurements will be evaluated and compared.

The Effect of Transcutaneous Stimulation on Blood Pressure in Spinal Cord Injury (SCI)

This project will investigate the effect of spinal cord transcutaneous stimulation on blood pressure in individuals with a chronic spinal cord injury who experience blood pressure instability, specifically, orthostatic hypotension (a drop in blood pressure when moving from lying flat on your back to an upright position). The main questions it aims to answer are: 1. What are the various spinal sites and stimulation parameters that normalize and stabilize blood pressure during an orthostatic provocation (70 degrees tilt)? 2. Does training, i.e., exposure to repeated stimulation sessions, have an effect on blood pressure stability? Participants will undergo orthostatic tests (lying on a table that starts out flat, then tilts upward up to 70 degrees), with and without stimulation, and changes in their blood pressure will be evaluated.

Deciphering the Mechanisms of Central BP Regulation in Patients With PD Associated With Orthostatic Hypotension

Phase 1 objective: test the feasibility of using a 3Tesla MRI scanner instead of a 7Tesla MRI scanner to measure brainstem responses to LBNP in healthy participants. Phase 2 primary objective: compare the brainstem responses to LBNP in patients with PD associated with OH to PD patients without OH using BOLD fMRI

Blood Pressure Effects on Cognition and Brain Blood Flow in PD

Parkinson's disease (PD) is the second most common neurodegenerative disorder worldwide. Besides causing symptoms that impair movement, PD also causes non-motor symptoms, such as problems thinking and orthostatic hypotension (OH), i.e., low blood pressure (BP) when standing. About one-third of people with PD have OH, which can cause sudden, temporary symptoms while upright, including lightheadedness, dizziness, and fainting. People with PD and OH can also experience problems thinking that happen only while upright and not while sitting - this can occur without other symptoms, such as feeling dizzy or faint. However, the level of low BP that can affect thinking remains unknown, and no guidelines exist for treating OH when it happens without symptoms. This is significant because OH could be a treatable risk factor for thinking problems in PD, but OH is often not treated if people do not report obvious symptoms. This project's goal is to determine how BP affects brain function in PD. The proposed experiments will measure BP and brain blood flow continuously in real-time using innovative wearable technology. Persons with PD with OH and without OH will undergo repeated cognitive tests while supine (lying down) and while upright. I will study the associations between BP, thinking abilities, and brain blood flow, and will compare groups with and without OH. These findings could be important because if a certain level of BP correlates with thinking abilities, then treating OH in PD may prevent thinking problems, which would improve health-related quality of life and reduce disability and healthcare costs.

Droxidopa / Pyridostigmine in Orthostatic Hypotension

This study is being done to study the combination of pyridostigmine and low-dose Droxidopa for the treatment of orthostatic hypotension.

Speed of Robotic Leg Movements and Orthostatic Hypotension in Subacute SCI

This study seeks to evaluate whether the speed (cadence) of lower extremity robotic movement has an impact on orthostatic hypotension and upright tolerance when training with the ErigoPro robotic tilt-stepper. It is hypothesized more frequent short-lasting leg movements (faster cadence) reduces the occurrence/severity of orthostatic hypotension better than less frequent longer-lasting leg movements (slower cadence).

Frequency of Orthostatic Hypotension in Patients Who Underwent Colonoscopy

Patients who will undergo colonoscopy accompanied by sedoanalgesia will be admitted at Aksaray Training and Research Hospital Gastroenterology Clinic between May and July 2024. Orthostatic hypotension will be evaluated after patients meet the discharge criteria in the postoperative recovery unit.

The Value of Near-infrared Spectroscopy and Blood Pressure Measurements in Estimating Future Fall Risk in Older Adults

The investigators aim to study which measurements/definitions from continuous blood pressures measurements (using a Finometer) and from cerebral oxygenation measurements (using near-infrared spectroscopy (NIRS)) are associated with future fall incidents in older adults at risk of falls.

Hypercapnia in Orthostatic Hypotension

The Autonomic (or "automatic") Nervous System (ANS) regulates internal processes, including control of heart rate and blood pressure (BP). When someone stands, and gravity tries to pull blood away from the brain, the ANS works to maintain BP and brain blood flow. Neurogenic Orthostatic Hypotension (NOH) occurs when our "fight-or-flight" part ("sympathetic") of the ANS fails. BP can drop a lot when upright, reducing blood flow and oxygen delivery to the brain, and this can cause symptoms of light-headedness, nausea, and fainting. One solution to help counter the effects of NOH may be to increase sympathetic activity by breathing higher levels of carbon dioxide. In healthy volunteers, small increases in the amount of inhaled carbon dioxide has been shown to increase BP in the upright position, and this improves symptoms! The objectives of the current study are to apply carbon dioxide in patients with NOH and healthy controls to: (a) evaluate the effects of breathing carbon dioxide on BP and brain blood flow, and (b) determine if a device that increases carbon dioxide while standing will work as a new therapy

The Effect of Water Carbonation on Orthostatic Tolerance

The primary purpose of this investigation is to determine whether water carbonation can improve orthostatic tolerance in healthy control volunteers. Orthostatic tolerance refers to the ability to maintain an adequate blood pressure when standing. In some individuals blood pressure can fall when standing, predisposing to dizzy spells or fainting episodes. Drinking water can boost blood pressure and making fainting episodes less likely. However, it is not clear whether the carbonation of the water has any further impact on the blood pressure response. This is important because it may be that carbonated water expands the stomach (gastric distension), provoking an increase in sympathetic activity. The increase in sympathetic nervous system activity boosts blood pressure. Resolving this question would have important implications for patients with syncope. This study will test whether carbonated water will have any further impact on blood pressure than the already known effect of non-carbonated water.

Autonomic Effects of Spinal Cord Stimulation in Spinal Cord Injury

The goal of this interventional crossover study is to determine the effects of transcutaneous spinal cord stimulation (TSCS) on the ability to perform moderate exercise and regulate core body temperature in the chronic spinal cord injury community. The main questions it aims to answer are: * What are the effects of active TSCS targeted for BP control on exercise endurance time and HR recovery during submaximal arm cycle ergometry (ACE) as compared to sham TSCS in participants with chronic, cervical SCI? * What are the effects of active TSCS on Tcore responses to cool ambient exposure and on subjective reporting of thermal comfort and thermal sensitivity as compared to sham TSCS. Participants will receive sham and active stimulation while using an arm bicycle or while in a cold room. Participants are free to participate in either the exercise phase, the cold room phase, or both phases of this study. Please note that there no expected long term benefits of this study.