Active clinical trials for "Syncope, Vasovagal"

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.

This study is a prospective, single-center randomized controlled clinical trial. patients with refractory vasovagal syncope were randomly divided into two groups according to the proportion of 1:1. Group A: simple left atrial ganglion plexus ablation (RAGP + LSGP + LLGP + LIGP + RIGP ablation); B group: left atrial ganglion plexus combined with right atrial ganglion plexus ablation (group A + consolidation ablation of RAGP at the junction of right atrial septum and superior vena cava). To clarify the role of RAGP in cardiac autonomic nervous system and the effect of ablation, to establish the standard stragtegy of cardiac nerve ablation.

Syncope affects about 50% of Canadians, is the cause of 1-2% of emergency room visits, and probably is responsible for CDN $250 million in health care spending each year. It is associated with decreased quality of life, trauma, loss of employment, and limitations in daily activities. The most common cause is vasovagal syncope. This occurs in people of all ages, and is a lifelong predilection. While the median number of faints in the population is 2, those who come to the investigators care have a median 10-15 lifetime spells, and have an increased frequency in the year before presentation. Vasovagal syncope is due to abrupt hypotension and transient bradycardia, which cause cerebral hypoperfusion. The pathophysiology may be either failure of venous return or progressive vasodilation, both due to inappropriately low sympathetic outflow. Sympathetic stimulation might be involved early in the reflex cascade. There is no known medical treatment for frequent fainting. The investigators performed the pivotal CIHR-funded randomized trials that showed that neither permanent pacing, beta blockers, nor fludrocortisone help the majority of patients. However 3 observational studies suggested that beta blockers prevent syncope in older subjects, and the Prevention of Syncope Trial (POST1) showed in a prespecified, -stratified analysis that patients ≥42 years tended to benefit. The investigators recent meta-analysis showed a benefit from metoprolol in these patients, with a hazard ratio of 0.52 (CI 0.27 to 1.01), and an age-specific response to beta blockers (p = 0.007). These results suggest the need for a randomized clinical trial of metoprolol for the prevention of vasovagal syncope in older subjects. Accordingly,the investigators conducted a poll of 48 cardiologists and neurologists in Canada and abroad: 98% stated that a randomized trial was necessary, and 92% agreed to participate in such a trial. Separately, this study emerged as the first choice for syncope randomized trials after consultation with Canadian and international experts. Objective: To determine if treatment with metoprolol in patients ≥40 years old with moderate to severely frequent vasovagal syncope will better suppress syncope recurrences than placebo. Methods: This will be a longitudinal, prospective, parallel design, placebo-controlled, randomized clinical trial. Patients will be enrolled during a recruitment period of 4 years and followed for a fixed period of 1 year. Subjects will have had ≥1 faint in the previous year, and a diagnosis of vasovagal syncope based on a quantitative diagnostic score. They will be randomized to receive either metoprolol or placebo at an initial dose of 50 mg bid. Dose adjustments will be made according to treating physician discretion to optimize tolerance and compliance while maximizing dose. The primary outcome measure will be the time to the first recurrence of syncope (after a 2 week dose titration wash-in period) over the 1-year observation period. The primary analysis will be performed on an intention-to-treat basis. Secondary analyses will include an on-treatment analysis, as well as analyses comparing syncope and presyncope frequency, number needed to treat, quality of life, impact of syncope on daily living, and cost from the perspective of the publicly funded health care system. The investigators will enroll 248 patients to have an 85% power to detect a reduction (p<0.05) in the primary outcome from 50% (placebo group) to 30% (midodrine group), a 40% relative risk reduction. This sample size also allows for a 11% rate of subject dropout with loss to follow-up before a syncopal event. The University of Calgary Syncope Clinic has a well-functioning clinical trial apparatus that successfully completed the randomized, multicenter Prevention of Syncope Trials (POST1: metoprolol for vasovagal syncope; POST2: fludrocortisone for vasovagal syncope) and SIRCAT (Statin-Induced Reduction of Cardiomyopathy Trial). Enrolment is underway in the CIHR-funded POST3 (pacing versus loop recorders in syncope patients with bifascicular block) and POST4 (midodrine for vasovagal syncope). Study centres that were highly productive in POST1-4 have agreed to participate. The investigators therefore will have ample syncope enrolling centres. Relevance: This study will provide evidence to inform the use of metoprolol in the treatment of moderate to severely frequent syncope in older patients with vasovagal syncope. Given the lack of any other conventional medical therapy the investigators expect it to have rapid impact on care.

Vasovagal syncope (VVS, simple faint) is the most common cause of transient loss of consciousness and represents the acute episodic form of orthostatic intolerance (OI). Postural tachycardia syndrome (POTS) is the common chronic form of OI. Both are defined by debilitating symptoms and signs while upright relieved by recumbency. Northera should therefore improve both sympathetic splanchnic arterial vasoconstriction and sympathetic splanchnic venoconstriction in POTS and VVS, and may represent an ideal drug to improve the orthostatic response in POTS and VVS.

About 20% of adults faint recurrently. These patients are often highly symptomatic, have problems with employment and driving and have reduced quality of life. There are no therapies that have withstood the test of adequately designed and conducted randomized clinical trials. Midodrine is a prodrug whose metabolite is an alpha-1 adrenergic agonist that increases venous return to the heart and raises blood pressure. There is considerable lower level evidence that it might prevent vasovagal syncope. The investigators will test the hypothesis that Midodrine prevents recurrences of syncope in patients with moderate to severe vasovagal syncope.

Reflex syncope is the most common form of syncope. It can lead to injuries and affect quality of life. Nonpharmacological and medical therapies have limited effectiveness. In certain patients, cardiac pacing seem to be beneficial. More recently cardioneuroablation (CNA) has emerged as a novel therapy for reflex syncope. The investigators aim to determine whether CNA is more effective than cardiac pacing at reducing the rate of cardioinhibitory-type reflex syncope.

About 20% of adults faint recurrently. These patients are often highly symptomatic, have problems with employment and driving, can be injured, and have poor quality of life. There are few therapies that have withstood the test of randomized clinical trials. the investigators will conduct a prospective, randomized, parallel, double-blind, proof-of-concept study that tests the hypothesis that serotonin 5HT3 receptor inhibition with ondansetron prevents tilt-induced vasovagal syncope (VVS) and pre-syncope in patients with clinical VVS. A total of 70 patients with quantitative clinical diagnostic criteria for VVS and at least 1 syncopal spell in the preceding year will be randomized in a double-blind acute phase 2 study to ondansetron 8 mg PO BID x 2 doses or matching placebo. The endpoint will be presyncope or syncope associated with diagnostic hemodynamic changes. These data should provide useful preliminary data as a foundation on which to conduct a subsequent randomized clinical trial.

Vasovagal Syncope (simple postural faint) is the most common cause of acute loss of consciousness. Postural tachycardia syndrome(POTS) is the most common chronic form of postural lightheadedness. Together they afflict many Americans, mostly young women, who are prevented from gainful employ or school attendance. The underlying mechanism is not known. Our past work suggests that a simple molecule, nitric oxide, acts to subvert normal blood flow controls causing blood to pool in the gut when standing. Our proposal will show the mechanism behind this problem and will indicate effective medical treatments. Patients will be compared to healthy control subjects.

Background: Autonomic system modification is an established therapeutic approach that has been increasingly used for the treatment of vagal-related symptomatic bradycardia, such as cardio-inhibitory vasovagal syncope1-12. Although convincing results had been reported from small populations, a large randomized study providing robust evidence on the efficacy of this approach has not yet been performed. Hypothesis: Cardiac autonomic system modification is effective for the treatment of vagal-related symptomatic bradycardia, and is associated better clinical results as compared to placebo.

The essential arterial hypotension and allostasis registry is a prospective, observational research that has the purpose of demonstrating that essential blood pressure (BP) disorders and the associated comorbidities are a result of the inappropriate allostatic response to daily life stress. This required a functioning brain orchestrating the evaluation of the threat and choosing the response, this is a mind-mediated phenomenon. If the response is excessive it contributes to high BP, if deficient to low BP, and the BP itself will identify the allostatic pattern, which in turn will play an important role in the development of the comorbidities. To do so, consecutive patients of any age and gender that visit a cardiologist's office in Medellin, Colombia, are recruited. Individuals are classified according to their arterial BP and allostasis and follow them in time to see what kind of diseases develops the most (including BP) in the follow up according to the categorization of the characteristic chosen and after adjustment for confounder's variables. In addition, stress events with their date are registered. HYPOTHESIS The causes of the diseases are multifactorial. Physical, biochemical, psychological, social, and cultural dimensions of development dynamically interact to shape the health development process. A person´s health depends on their: Biological and physiologic systems External and internal environment (a) physical, b) internal behavioural and arousal state as registered by the brain. Their interaction. The allostatic mechanisms to the internal and external stressors (allostatic load) involves a network composed by: Functional systems; mediated by: The Autonomic Nervous System The endocrine system The immune system Structural changes: whenever the internal and/or external stressors are long lasting and/or strength enough, they may induce changes in: Epigenetic, endophenotypes, polyphenism. Plasticity The interaction between a) and b). The network response do not affect exclusively the BP, propitiating the development of comorbidities, which may prompt strategies for prevention, recognition and ultimately, treatment. The allostatic model defines health as a state of responsiveness. The concept of psycho-biotype: The allostasis is the result of both: biological (allostasis) and psychological (psychostasis) abilities. It is proposed that both components behave in similar direction and magnitude. Immune disorders may be associated with the development of cancer. High BP population has a higher sympathetic and lower vagal tone, this has been associated with a decrease in the immune´s system function. Resources and energy depletion: Terms like weathering have been used to describe how exposures to different allostatic loads gradually scrape away at the protective coating that keeps people healthy. It is postulated that High BP individuals have more resources and energy.