View clinical trials related to Neurocardiogenic Syncope.
Filter by:The purpose of this study is to evaluate the effectiveness of cardioneuroablation for the treatment of neurocardiogenic syncope (NCS), also known as "vaso-vagal" syncope. Syncope is a general term for passing out spells and neurocardiogenic syncope is a specific form of passing out spells caused by sudden drops in heart rate or blood pressure. Although the specific mechanisms of NCS are not well understood, it is believed that some people are prone to developing passing out spells in specific situations such as standing up for a long period of time, pain or nausea. In these situations, the body reacts with a paradoxical reflex which leads to a drop in blood pressure and heart rate and causes passing out. Certain types of medications are used to treat NCS including beta-blockers, midodrine and florinef, among others. However, none of these medications are particularly effective at preventing passing out spells and many people continue to have episodes despite trying different medications. Cardioneuroablation is a new form of treatment for NCS. The term ablation means using a wire to make small electrical burns in the heart. Ablation has been used for many years to treat other electrical disturbances in the heart but the use of ablation to treat NCS is a new application. The goal of cardioneuroablation is to identify areas within the heart which are believed to initiate the reflex which triggers the drop in heart rate and blood pressure that leads to passing out. In preliminary studies, it has been suggested that cardioneuroablation may be significantly more effective than medications at preventing passing out spells for people with NCS. Hypothesis: Cardioneuroablation of vagal inputs in the left atrium may serve as an effective treatment modality for the prevention of NCS by blunting the initial trigger of the cascade that leads to symptoms and syncope.
Dysautonomia, primarily defined as postural orthostatic tachycardia syndrome (POTS) can seriously disrupt a child's daily activities. It is most commonly associated with nausea or abdominal pain. In preliminary studies, when orthostatic intolerance was treated with fludrocortisone, a standard therapy for orthostatic intolerance (OI), symptomatic improvement in nausea was observed. However, children with POTS were also observed to have higher supine mean arterial pressure (MAP) (preliminary data) and greater suppression of the baroreceptor reflex sensitivity (BRS) occurred upon up-right tilt. While fludrocortisone alleviates nausea associated with OI, its long-term use may pose long term health risks to children including worsening hypertension. Therefore, it is the objective of this study to define the mechanism for OI as it relates to nausea. The investigators hypothesize that OI resulting from changes in the autonomic nervous system is the likely mechanism for the nausea observed in the patients in this study. The investigators further hypothesize that this is potentially an early marker for future cardiovascular problems such as early onset hypertension and cardiac hypertrophy. The general objective of this protocol is to address this gap in knowledge by determining the autonomic characteristics of children with OI as well as defining neurohumoral profiles for these subjects to better understand the cause of the elevated supine in these subjects. By better understanding the potential mechanism for this condition, it is the investigators future goal to develop a more focused and safer treatment strategy. The investigators will study subjects between 10 to 18 years of age utilizing the tilt table to mimic daily life stressors and also measure serum levels of epinephrine, norepinephrine, rennin, angiotensin II, aldosterone, and vasopressin at baseline and during tilt. This study will generate data with high impact in that more rational treatments for management of dysautonomia could be chosen on the basis of the profile of dysautonomia and neurohumoral markers.
This study will examine the effectiveness of the drug propranolol in preventing fainting in patients with sympathoadrenal imbalance (SAI). SAI is a particular pattern of nervous system and chemical responses in which the blood vessels in skeletal muscles do not remain constricted appropriately during standing for a long time. This can lower blood pressure and cause fainting. Propranolol Inderal (registered trademark) is a Food and Drug Administration-approved drug that belongs to a class of drugs called beta-blockers. These drugs slow the heart rate and maintain blood pressure in certain situations. Patients 18 years of age and older with SAI may be eligible for this study. Screening includes a tilt table test, described below, to determine if the patient has a particular chemical pattern in the blood. Patients enrolled in the study take propranolol pills in increasing doses during the first week of the study to determine the proper dose for the individual. Then, the drug is stopped until the experimental phase of the study begins. In this phase, patients are randomly assigned to take either propranolol or placebo (look-alike pill with no active ingredient) for 4 days. On the fourth day, the patient undergoes a tilt table test to determine whether the treatment affects the patient's ability to tolerate tilt. For this test, the patient lies on a padded table with a motorized tilt mechanism that can move the patient from a flat position to an upright position in about 10 seconds. The patient remains upright for up to 45 minutes while the following measurements are taken: - Arterial blood pressure monitoring and arterial blood sampling. A catheter (thin, plastic tube) is inserted into an artery in the elbow crease area of the arm or the wrist. This catheter allows continuous blood pressure monitoring and sampling of arterial (oxygenated) blood during the tilt test. - Venous blood sampling and measurement of epinephrine and norepinephrine release. A catheter is inserted into a vein in each arm, one to collect venous (deoxygenated) blood samples, and the other to inject radioactive epinephrine (adrenaline) and norepinephrine (noradrenaline). These radioactive drugs, or ,tracers, allow measurement of the rate of release of the body's own norepinephrine and epinephrine into the bloodstream. - Physiologic measurements. Blood pressure, heart rate, and EKG are measured continuously during the tilt test session, and blood flows and skin electrical conduction are measured intermittently. Blood flow is measured using sensors applied to the skin and a blood pressure cuff around the limb. For skin blood flow measurements, a laser beam scans the skin surface. The skin electrical conduction test measures how well the skin conducts electricity. This is measured through sensors placed on the fingers or other sites. The effects of the test drug are allowed to wear off for 1 week, after which the entire tilt test procedure is repeated. Patients who were given propranolol for the first test session take placebo for the repeat session, and those who were given placebo take propranolol.