Clinical Research Directory

Continuous and Non-invasive Measurements by Task Force® CORE/CARDIO in Autonomic Function Testing (AFT)

Background: The investigational device, "Task Force® CORE" (TFC, CNSystems Medizintechnik GmbH, Graz, Austria) together with the "Task Force® CARDIO" (TFCARDIO, CNSystems Medizintechnik GmbH, Graz, Austria) medical device software, is a new CE-marked medical device for continuous non-invasive determination of blood pressure (BP), cardiac output (CO) and derived parameters based on the well established CNAP® (continuous non-invasive arterial pressure) technology by CNSystems. Aim: The primary aim of this prospective, method comparison, open study is data acquisition for the performance evaluation of the TFC during autonomic function testing in comparison with an clinically accepted reference method. Setting: The setting of the clinical investigation will be the autonomic function testing laboratory at the Department of Neurology, the University Hospital Center Zagreb. Inclusion criteria: Patients who are over 18 years and who provide written informed consent. Sample size: The study has an calculated sample size of 70 patients. Considering a drop-out rate of 5%, a total of 75 patients will be included. Statistics: Descriptive statistics, values for the percentage error and correlation estimates will be derived. Furthermore, scatterplot, Bland-Altman analysis, concordance analysis of parameter changes and further comparative statistics will be performed.

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.

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.

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.

The STAND-UP Study

Orthostatic hypotension (OH) and orthostatic intolerance (OI) are common conditions where blood pressure drops when standing up, causing dizziness, fainting, or fatigue. These affect up to 30% of adults over 65 and raise risks for heart disease, stroke, kidney problems, and more. Current medications often don't fully help and can cause side effects like high blood pressure when lying down. The STANDUP study tests a new approach: using a minimally invasive procedure to open narrowed veins above the heart (supracardiac veins) that may block blood flow back to the heart. We believe fixing these blockages could improve blood pressure control and reduce symptoms. This is a 2-year study enrolling 100 adults (age 18+) with OH or OI that hasn't improved with standard treatments or is worsened by lying-down high blood pressure. What happens in the study? Participants get imaging (like X-rays and ultrasound) to check for vein narrowing. If needed, doctors use a thin tube (catheter) through a small skin puncture to inflate a tiny balloon (angioplasty) or place a small mesh tube (stent) to widen the veins. The procedure takes a few hours under local anesthesia, with monitoring for safety. Follow-up visits check symptoms, blood pressure, and quality of life at 2-4 weeks, 3 months, 6 months, 1 year, and 2 years. Who can join? Adults 18+ with diagnosed OH/OI not helped by meds. Must give informed consent. Not eligible if: Pregnant, breastfeeding, actively infected, or unable to take blood thinners. Possible benefits: Better standing tolerance, fewer symptoms, improved daily life, less need for meds, and new knowledge on vein issues in OH/OI. Risks: Rare but include bleeding, infection, stroke, vein clots, stent issues, radiation from imaging, or temporary symptom worsening. We'll monitor closely and report any problems. This single-arm trial (no placebo group) will compare before-and-after results to see if the procedure helps. No study drug costs; covered by insurance or clinic. Led by Dr. Karthikeyan Arcot at St. Francis Hospital, Roslyn, NY. Contact for details.

Autonomic Dysfunction in Patients Following Bariatric Surgery: The ADiPOSE Study

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.

Effects of Age, Sex and Isometric Exercise on Ventricular-Vascular Interactions During Cardiac Unloading

As people get older, especially women, they often feel dizzy or even faint when they go from sitting or lying down to standing up. This happens because their blood pressure (BP) drops, which can lead to falls, heart problems, and even death in older adults. When BP changes, it affects how well the heart works and how it talks with blood vessels. However, little research has been done on how the heart and blood vessels talk during times of low BP. The crosstalk between the heart and blood vessels is important, as it allows enough blood and oxygen to reach the brain and other vital organs. Some research shows that as we get older, the crosstalk does not work as well. This can make it harder for blood to flow properly or put extra pressure on the heart and arteries. That's why we want to study how the heart and blood vessels talk during a laboratory-simulated situation of low BP in young and older men and women. In our study, participants will lie down with their lower body in a chamber that creates a vacuum around their legs. This safely mimics what happens when you stand up quickly. We can then measure heart function, the stress on arteries, and BP while your legs are in that vacuum. We'll use an ultrasound to check the heart and a finger cuff to measure BP. We'll also see if gripping something firmly can help protect from sudden drops in blood pressure. This study will help us understand more about a condition called orthostatic hypotension and might even suggest that handgrip exercise could prevent it. The main questions the current study aims to address are: * Does the cross-talk between the heart and vessels become more impaired with aging during laboratory-simulated conditions of low BP? * Do women have worse crosstalk between the heart and blood vessels during laboratory-simulated conditions of BP? * Does hand gripping protect against drops in BP during conditions of low BP? All participants will be asked to * Complete two laboratory conditions on two separate days with a randomized order (like flipping a coin): * Exposure to a lower body negative pressure (LBNP) chamber to safely simulate low BP (control) * Exposure to a lower body negative pressure (LBNP) while conducting hand-squeezingexercise (experimental). The investigators will examine how heart and blood vessel interactions, as well as blood pressure (BP) responses, differ in young and older adults of both sexes when exposed to a laboratory-simulated low BP condition (LBNP), both with and without hand squeezing exercise.

Postural Sway and Counterpressure Maneuvers for Pediatric Syncope

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.

Paediatric Syncope in the Emergency Department

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.

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