Materiały źródłowe

• #1 Vasovagal Episode – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK470277/

  Vasovagal syncope is the most common form of syncope in adults. More than 85% of syncopal events in people younger than 40 years are attributable to vasovagal syncope. Even in geriatric patients, more than 50% of syncopal episodes are due to vasovagal syncope. Vasovagal syncope requires an intact and functioning autonomic nervous system, and therefore, its incidence is low in populations with autonomic nervous system dysfunction, such as patients with Parkinson disease. The lifetime incidence of an episode of vasovagal syncope is more than 33%.

• #1 Vasovagal Episode – StatPearls – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK470277/

  A vasovagal episode or vasovagal syncope is the most common form of reflex syncope. Reflex syncope describes any form of syncopal episode caused by a failure in the autoregulation of blood pressure, and ultimately, a drop in cerebral perfusion pressure resulting in a transient loss of consciousness. The mechanisms responsible for this are complex and can both depression of cardiac output as well as decreased vascular tone. […] The etiology of vasovagal syncope is unclear. Some believe that the vasovagal reaction is an exaggeration of an adaptive response meant to assist in hemostasis in times of trauma. In other words, in the setting of physical trauma, the body reflexively lowers blood pressure and heart rate to reduce the amount of bleeding. Others have sought a genetic link for the syndrome. Research elucidating a genetic predisposition for vasovagal syncope is challenging due to the high background incidence of the disease, but genomic analysis demonstrates some differences in copy number variations in families with a high burden of reflex syncope. More research in this area is warranted.

• #2 Vasovagal syncope – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/vasovagal-syncope/symptoms-causes/syc-20350527

  Vasovagal syncope occurs when the part of your nervous system that regulates heart rate and blood pressure overreacts to a trigger. Common triggers include: […] During a vasovagal syncope episode, your heart rate slows, and the blood vessels in your legs widen. This allows blood to pool in your legs, which lowers your blood pressure. The drop in blood pressure and slowed heart rate quickly reduce blood flow to your brain, and you faint. […] Vasovagal syncope can happen without a trigger.

• #3 Vasovagal Syncope: Symptoms, Causes & Treatment

  https://my.clevelandclinic.org/health/diseases/23325-vasovagal-syncope

  Vasovagal syncope happens when your nervous system overreacts, and you pass out from things like feeling anxiety or exhaustion or seeing needles. […] This is the most common type of reflex syncope, which happens automatically for reasons you cant control. People also sometimes call it neurocardiogenic syncope because factors involving your heart, brain or both cause it. […] Vasovagal syncope is a reflex reaction to something going on around you. But the reflex is either too strong or happens at the wrong time. This all starts in the part of your nervous system that works without you having to think about it your autonomic nervous system. […] One of the key nerves in this system is the vagus nerve, which controls your heart rate and blood pressure. If your vagus nerve becomes too active, it can cause your heart rate and blood pressure to drop too much or too quickly (or both).

• #3 Vasovagal Syncope: Symptoms, Causes & Treatment

  https://my.clevelandclinic.org/health/diseases/23325-vasovagal-syncope

  If your blood pressure drops too much, this causes vasovagal syncope. You pass out because your brain isnt getting enough blood flow. […] Something happening to you or near you almost always brings on vasovagal syncope. Triggers can be things you see or feel that upset you. Common triggers include: Needles or medical instruments. This includes blood draws, blood donations or the sight of certain medical tools or instruments, like scalpels. […] Seeing blood. Fainting at the sight of blood is also a common cause of vasovagal syncope. […] Stress, anxiety or emotional upset. Strong emotions or pain can cause you to pass out. […] Fatigue or exhaustion. Over-exertion, even just from standing too long, can be enough to cause you to pass out.

• #4 VASOVAGAL SYNCOPE AND CHRONIC VAGAL EXCESS – Dr. Nicholas L. DePace, M.D., F.A.C.C.

  https://franklincardiovascular.com/vasovagal-syncope-and-chronic-vagal-excess/

  Vasovagal Syncope is also known as a simple fainting spell. […] It is mediated by a neurological reflex within the body. […] This reflex causes a sudden dilatation of the blood vessels of the legs where pooling of blood occurs in the lower extremities. […] It can also cause a slow heart rate sometimes down to 20 beats per minute, which can also lead to reduced cardiac output. […] Oftentimes, Vasovagal Syncope is known as neurocardiogenic syncope or reflex syncope. […] The Vagus nerve is also important in lowering heart rate and blood pressure. […] When it becomes overactive it can prevent the heart rate from pumping blood to the brain, which can occur with Vasovagal Syncope. […] Excess in Vagus activity intermittently can cause loss of consciousness. […] Vasovagal Syncope can be precipitated by emotional stress or standing upright for long periods of time, or even prolonged sitting.

• #5 Syncope (medicine) – Wikipedia

  https://en.wikipedia.org/wiki/Syncope_(medicine)

  Vasovagal (situational) syncope is one of the most common types which may occur in response to any of a variety of triggers, such as scary, embarrassing or uneasy situations, during blood drawing, or moments of sudden unusually high stress. […] There are many different syncope syndromes which all fall under the umbrella of vasovagal syncope related by the same central mechanism. […] First, the person is usually predisposed to decreased blood pressure by various environmental factors. […] The next stage is the adrenergic response. […] If there is underlying fear or anxiety (e.g., social circumstances), or acute fear (e.g., acute threat, needle phobia), the vaso-motor centre demands an increased pumping action by the heart (flight or fight response). […] A feedback response to the medulla is triggered via the afferent vagus nerve.

• #5 Syncope (medicine) – Wikipedia

  https://en.wikipedia.org/wiki/Syncope_(medicine)

  The abnormality lies in this excessive vagal response causing loss of blood flow to the brain. […] The tilt-table test typically evokes the attack. Avoiding what brings on the syncope and possibly greater salt intake is often all that is needed. […] Associated symptoms may be felt in the minutes leading up to a vasovagal episode and are referred to as the prodrome. […] Vasovagal syncope can be considered in two forms: […] Isolated episodes of loss of consciousness, unheralded by any warning symptoms for more than a few moments. […] Recurrent syncope with complex associated symptoms. […] Syncope has been linked with psychological triggers. […] This includes fainting in response to the sight or thought of blood, needles, pain, and other emotionally stressful situations. […] One theory in evolutionary psychology is that fainting at the sight of blood might have evolved as a form of playing dead which increased survival from attackers and might have slowed blood loss in a primitive environment.

• #5 Syncope (medicine) – Wikipedia

  https://en.wikipedia.org/wiki/Syncope_(medicine)

  „Blood-injury phobia”, as this is called, is experienced by about 15% of people. […] It is often possible to manage these symptoms with specific behavioral techniques. […] Another evolutionary psychology view is that some forms of fainting are non-verbal signals that developed in response to increased inter-group aggression during the Paleolithic. […] A 2023 study identified neuropeptide Y receptor Y2 vagal sensory neurons (NPY2R VSNs) and the periventricular zone (PVZ) as a coordinated neural network participating in the cardioinhibitory Bezold-Jarisch reflex (BJR) regulating fainting and recovery.

• #6 What is Neurocardiogenic Syncope? | Northwest Functional Neurology

  https://www.northwestfunctionalneurology.com/blog/what-is-neurocardiogenic-syncope

  Neurocardiogenic syncope is the result of a part of the lower brainstem producing a sudden excessive output. The lower third of the brainstem is called the medulla, which contains the vasodepressor system. This is part of the parasympathetic system, and when it fires it drives the Vagus nerve to drive the syncopal response. […] In Neurocardiogenic Syncope, a trigger such as a sudden fright or panic attack will lead to an exaggerated increase in sympathetic tone. This will increase the heart’s rate and force of contraction. This stimulates cardiac C fibers, which drives the vasodepressor system. This has an excessive response, and promotes a sudden drop in heart rate and blood pressure. […] Syncope itself is a benign event, often causing nothing more than embarrassment. A sudden fall, however, can lead to injury. It is common for people living with vasovagal syncope to suffer frequent concussions and mild traumatic brain injuries. These often affect the brainstem, which can increase the syncopal response and can lead to more frequent syncopal attacks.

• #7

  https://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/cardiology/syncope/

  Vasovagal syncope, also known as neurocardiogenic syncope, is commonly described using the Bezold-Jarisch reflex model, where a reduction in ventricular preload stimulates mechanoreceptors in the inferoposterior part of the left ventricle leading to a vigorous contraction. This causes an increased afferent discharge of the unmyelinated C fibers from the ventricular mechanoreceptors and the central nervous system responds with reflex sympathetic withdrawal and increased parasympathetic output. These signals cause vasodilation, hypotension and bradycardia. This ineffective reflex response causes venous pooling in the periphery or splanchnic regions or both with paradoxical vasodilation leading to further hypotension and loss of consciousness. […] Other potential mechanisms include involvement of central serotonergic pathways and release of endogenous opioids or catecholamines. Vaddadi et al described 2 phenotypes in patients with recurrent vasovagal syncope, both associated with reduced norepinephrine availability: 1 phenotype with low pressure (systolic blood pressure less than 100 mm Hg) and low tyrosine hydroxylase levels; and 1 phenotype with normal pressure (systolic blood pressure greater than 100 mm Hg) and increased norepinephrine reuptake.

• #7

  https://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/cardiology/syncope/

  Reflex syncope includes vasovagal syncope, situational syncope, carotid sinus syncope, and atypical forms, which are a result of an inappropriate cardiovascular reflex in response to a trigger. Reflex syncope can be classified based in the type of efferent response: vasodepressor if hypotension due to loss of upright vasoconstriction tone predominate; cardioinhibitory if bradycardia or asystole predominate. […] Syncope due to orthostatic hypotension (OH) is defined as reduction in systolic blood pressure of at least 20 mm Hg accompanied by a diastolic blood pressure decrease of at least 10 mm Hg with upright posture. OH syncope includes syncope due to various types of primary and secondary autonomic dysfunction. The autonomic nervous system is the main effector in the hemodynamic response to standing and any deviation from the normal response to a postural stressor will lead to postural hypotension. […] The pathophysiology of syncope is summarized as a reduction in systemic blood pressure that causes a decrease in the global cerebral blood flow, which results in loss of consciousness. A sudden cessation of cerebral blood flow for 6 to 8 seconds has been shown to cause loss of consciousness.

• #7

  https://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/cardiology/syncope/

  Vasovagal syncope usually occurs with an upright posture held for more than 30 seconds (postural challenge) or with exposure to emotional stress, pain or a medical setting. It is characterized by prodromal features of presyncope, diaphoresis, a sense of warmth, flushing, nausea, abdominal discomfort, blurry vision, and vision loss. While unconscious, the patient is usually motionless. […] The Task Force for the Diagnostic Management Syncope of the European Society of Cardiology (Task Force of the ESC) has classified syncope into 3 main categories: reflex syncope, syncope due to OH, and cardiac syncope. Prospective studies have found that neurally mediated causes of syncope account for the largest percentage of events (38% to 56%). Cardiovascular causes, separated into syncope due to OH (2% to 24%) and structural heart disease (11% to 23%) account for smaller percentages of cases. The cause of syncope is undetermined in 14% to 18% of events.

• #8 Confirmation

  https://handbook.bcehs.ca/clinical-resources/clinical-references-cards/causes-of-syncope/

  Vasovagal (neurocardiogenic) […] Common cause of Neuro-cardiogenic syncope (aka, vasovagal syncope) […] Adrenergic stimuli (pain/emotion) […] Exaggerated catecholamine release […] Vasodilation / Bradycardia ++ […] — SYNCOPE

• #9 Reflex syncope – Wikipedia

  https://en.wikipedia.org/wiki/Reflex_syncope

  Reflex syncope is divided into three types: vasovagal, situational, and carotid sinus. […] Vasovagal syncope is typically triggered by seeing blood, pain, emotional stress, or prolonged standing. […] Reflex syncope occurs in response to a trigger due to dysfunction of the heart rate and blood pressure regulating mechanism. When heart rate slows or blood pressure drops, the resulting lack of blood to the brain causes fainting. […] Typical triggers include: prolonged standing, emotional stress, pain, the sight of blood, fear of needles, and time varying magnetic field. […] Regardless of the trigger, the mechanism of syncope is similar in the various vasovagal syncope syndromes. […] This results in a spectrum of hemodynamic responses: on one end of the spectrum is the cardioinhibitory response, characterized by a drop in heart rate and in contractility leading to a decrease in cardiac output that is significant enough to result in a loss of consciousness.

• #9 Reflex syncope – Wikipedia

  https://en.wikipedia.org/wiki/Reflex_syncope

  On the other end of the spectrum is the vasodepressor response, caused by a drop in blood pressure without much change in heart rate. […] The majority of people with vasovagal syncope have a mixed response somewhere between these two ends of the spectrum. […] Vasovagal syncope may be part of an evolved response, specifically, the fight-or-flight response.

• #10 Textbook | Vasovagal Syncope | Syncopedia

  https://syncopedia.org/vasovagal-syncope/

  Vasovagal syncope, also called a common faint, is a brief loss of consciousness due to a vasovagal reflex. The vasovagal reflex is the combination of: sympathetic withdrawal causing vasodilation (vaso), and parasympathetic (vagal) disinhibition causing bradycardia. It is thus a combination of vasodilation and bradycardia. When blood pressure falls and the supply of oxygen to the brain is not sufficient, syncope occurs. Syncope is defined as transient (short) loss of consciousness (amnesia, fall, unresponsive) due to cerebral hypoperfusion. […] Vasovagal syncope has two different triggers from a pathophysiological viewpoint. A combination of the triggers below is also possible. […] Vasovagal syncope can be triggered by prolonged standing. This is called an orthostatic vasovagal syncope (not to be confused with orthostatic hypotension). The most common trigger for orthostatic vasovagal syncope is prolonged standing, but combinations with triggers like a hot environment can cause vasovagal syncope to occur much earlier.

• #10 Textbook | Vasovagal Syncope | Syncopedia

  https://syncopedia.org/vasovagal-syncope/

  Vasovagal syncope can also be triggered by strong emotions. Specific emotional events that are often a trigger for vasovagal syncope are: Pain, Fear (e.g. blood phobia), Foul smell. […] The vasovagal reflex consists of vasodilation (vaso) and bradycardia/asystole via the vagal nerve (vagal). These factors produce a fall in blood pressure, ultimately resulting in cerebral hypoperfusion and syncope. […] In vasovagal syncope, recognizing the diagnosis is the first part of the treatment. As it is an episodal event, most patients dont need more than a few lifestyle measures to learn how to prevent the vasovagal faints.

• #11 Vasovagal syncope: Treatments, causes, symptoms, and more

  https://www.medicalnewstoday.com/articles/327406

  If someone is experiencing severe constipation, they may faint when passing a stool due to increased pressure in the rectum. […] When a person is in a hot environment, and their core temperature is reaching a dangerous level, the body will divert blood to the surface of the skin to cool itself down and prevent overheating. […] Exercise-induced VVS is rare, and doctors must rule out other life threatening diseases, including heart disease and arrhythmia, before confirming a diagnosis. […] Researchers are not sure what causes VVS during exercise, but they think that the Bezold-Jarisch reflex a type of inhibitory reflex that lowers blood pressure could be responsible. […] VVS does not typically require treatment. […] According to a 2016 review, limited treatment options are available for people with VVS.

• #12 Vasovagal Syncope: A Review of Current and Future Strategies – touchCARDIOLOGY

  https://touchcardio.com/syncope/journal-articles/vasovagal-syncope-a-review-of-current-and-future-strategies/

  Vasovagal syncope is common, and while it is usually associated with a benign prognosis, it results in significant physical and psychological morbidity for affected individuals. […] Despite advances in the understanding of the pathophysiology of VVS, significant uncertainty remains. Individuals with VVS represent a heterogenous patient population, and different mechanisms are likely to contribute. These mechanisms are still not fully understood. […] VVS is a neural reflex involving the autonomic nervous system. This is manifested by the vagally mediated Bezold-Jarisch reflex. In response to reduced filling of the left ventricle or the right atrium by reduced venous return (due to venous pooling in the splanchnic bed), parasympathetic activity is increased and sympathetic activation is decreased.

• #12 Vasovagal Syncope: A Review of Current and Future Strategies – touchCARDIOLOGY

  https://touchcardio.com/syncope/journal-articles/vasovagal-syncope-a-review-of-current-and-future-strategies/

  Neuroendocrine activity plays a part in the reflex probably as a protective mechanism and begins with vasopressin release, followed by epinephrine. […] The different heart rate and BP behaviours during orthostasis can be classified into collapse patterns, which are described and later modified by the Vasovagal Syncope International Study (VASIS). […] The ESC guidelines suggest that there is sufficient evidence to advise against beta blockers for prevention of recurrent VVS, while American guidelines state that they may be useful in individuals over 42 years old. […] Cardiac autonomic denervation was initially undertaken by endocardial identification of epicardial ganglionated plexi and their ablation, building upon neuromodulation targets for atrial fibrillation with encouraging early results. […] There are encouraging results from systematic case series data in support of CNA. A highly selected, very symptomatic group of patients with dominant cardioinhibitory VVS could benefit from CNA, by either completely abolishing syncope, or extending the prodrome long enough to prevent injury.

• #13 Evaluation and Management of Vasovagal Syncope | AAFP

  https://www.aafp.org/pubs/afp/issues/2001/0515/p2053.html

  Vasovagal syncope is characterized by the common faint, resulting from vagally mediated cardioinhibition. The resulting brady-cardia reduces cerebral blood flow to a level inadequate to maintain consciousness. […] The vagus nerve transmits afferent signals from the aortic arch baroreceptors, regulating arterial pressure. Increases in arterial flow stimulate efferent vagal outflow, inhibiting sympathetic drive and decreasing blood pressure. […] The vasovagal response is caused by excessive venous pooling that paradoxically results in vasodilatation and bradycardia rather than the appropriate physiologic responses of vasoconstriction and tachycardia. Other modulating factors that may be present during syncope include serotonin, adenosine and opioids. Nitric oxide has also been implicated in the vaso dilatory response associated with vasovagal syncope.

• #14 Pulsenotes | Vasovagal syncope

  https://app.pulsenotes.com/medicine/neurology/notes/vasovagal-syncope

  Vasovagal syncope is due to altered activation of the autonomic nervous system. […] Vasovagal syncope is a type of reflex syncope that causes loss of consciousness due to a reflex response in the autonomic nervous system. […] Vasovagal syncope, particularly in young patients, may be associated with specific triggers that lead to reflex autonomic nervous system changes. […] The result of these two mechanisms is a fall in blood pressure (hypotension) and subsequent reduction in cerebral perfusion (hypoperfusion). […] In vasovagal syncope, there is usually a combination of both cardioinhibitory and vasodepressors mechanisms, which is known as a mixed response. […] Vasovagal syncope is classically associated with a series of prodromal symptoms including nausea, pallor and sweating. […] The diagnosis of vasovagal syncope requires a thorough history and clinical examination.

• #14 Pulsenotes | Vasovagal syncope

  https://app.pulsenotes.com/medicine/neurology/notes/vasovagal-syncope

  The other major causes of syncope include orthostatic hypotension, arrhythmias, and structural cardiac or cardiopulmonary disease. […] Long-term management for vasovagal syncope is only required in recurrent cases. […] Medications may be used to prevent vasovagal syncope by improving blood pressure.

• #15 Vasovagal Syncope | Cedars-Sinai

  https://www.cedars-sinai.org/health-library/diseases-and-conditions/v/vasovagal-syncope.html

  Vasovagal syncope is a condition that leads to fainting in some people. It’s also called neurocardiogenic syncope or reflex syncope. It’s the most common cause of fainting. […] Several triggers can cause vasovagal syncope. […] To prevent fainting, stay out of hot places and don’t stand for long periods. […] Vasovagal syncope is the most common cause of fainting. It happens when the blood vessels open too wide or the heartbeat slows, causing a temporary lack of blood flow to the brain. […] It’s generally not a dangerous condition.

• #16 Vasovagal Syncope: Causes, Symptoms, and Treatment

  https://www.healthline.com/health/vasovagal-syncope

  Syncope means fainting or passing out. When fainting is caused by certain triggers, like the sight of blood or a needle, or an intense emotion like fear or fright, its called vasovagal syncope. Its the most common cause of fainting. […] Vasovagal syncope is caused by a sudden drop in blood pressure, often triggered by a reaction to something. This causes your heart to slow down for a short time. As a result, your brain may not get enough oxygen-rich blood, which causes you to pass out. […] This type of fainting episode is usually caused by certain triggers, like the sight of something that scares you, an intense emotion, getting overheated, or standing for too long.

• #17 Common triggers of vasovagal syncope and how to reduce your risk of fainting – Harvard Health

  https://www.health.harvard.edu/diseases-and-conditions/common-triggers-of-vasovagal-syncope-and-how-to-reduce-your-risk-of-fainting

  If you’ve ever fainted at the sight of blood or from standing up too fast, you’ve experienced what’s known as vasovagal syncope, the most common cause of fainting. Up to a third of people have experienced an episode of vasovagal syncope at some point in their lives. […] Vasovagal syncope occurs when the vagus nerve, which carries signals from the brain to the rest of the body and controls functions including heart rate and blood pressure, becomes overstimulated in response to triggers such as stress, dehydration, or donating blood. The heart rate slows and blood vessels widen, causing a drop in blood pressure and reduced blood flow to the brain. This can lead to a loss of consciousness. […] Common triggers of vasovagal syncope include prolonged standing, standing up too quickly from a sitting position, having blood drawn or donating blood, the sight of blood, dehydration, intense pain (such as from a back spasm), and sudden emotional stress or physical trauma. […] Not all fainting is related to the vasovagal nerve. Other common causes include heart problems, low blood sugar, panic disorder, seizure disorders, neurological disorders, substance use disorders, and some prescription medications.

• #18 Vasovagal Syncope: Symptoms, Causes, and Treatments

  https://www.verywellhealth.com/vasovagal-cardioneurogenic-syncope-1746389

  Vasovagal syncope happens when something triggers the vasovagal reflex, which causes blood vessels to widen (dilate) suddenly. Dilation of the blood vessels causes a lot of the blood in the body to pool in the legs. […] The pooling of blood is accompanied by a slowing heart rate, which leads to a drop in blood pressure. If the drop in blood pressure is big enough that the brain isn’t getting the oxygen it needs, a person faints. […] Vasovagal syncope is a reflex syncope, meaning it’s a response to a stimulus, including physical and psychological stress. Common triggers of vasovagal syncope include: dehydration, bleeding, sudden, severe pain, being exposed to a traumatic sight or event, high levels of stress, anxiety, or fear, straining while urinating or having a bowel movement, severe coughing, hyperventilation (breathing too fast), standing still for long periods of time, especially if you lock your knees, overexerting yourself in hot weather, excessive alcohol or substance use. […] There’s a strong link between vasovagal syncope and anxiety, and it can have a cyclical effect. Strong feelings of stress and anxiety can be a trigger for syncope, and repeated fainting spells can raise anxiety levels and lead to mental health conditions like depression.

• #19 Syncope: Symptoms, Causes & Treatments

  https://my.clevelandclinic.org/health/diseases/17536-syncope

  Vasovagal syncope happens when you have a sudden drop in blood pressure, which causes a drop in blood flow to your brain. It often occurs after standing for a while or under emotional distress. Normally, when you stand up, gravity makes blood settle in the lower part of your body, below your diaphragm. When that happens, your heart and autonomic nervous system work to keep your blood pressure stable. […] In vasovagal syncope, your heart rate and blood pressure inappropriately decrease severely. This causes decreased blood flow to your brain and leads to passing out. Typically, vasovagal syncope is benign.

• #20 Vasovagal Syncope Causes: The Hidden Neurological Factors Behind Children Fainting | PX Docs

  https://pxdocs.com/vagus-nerve/vasovagal-syncope-causes/

  Vasovagal syncope stems from a nervous system dysfunction rather than a structural heart or vessel issue. Certain triggers can set off an exaggerated neurological reflex or vasovagal response, sparking a precipitous drop in heart rate and blood pressure. By recognizing these common triggers, parents can become empowered to help minimize or prevent fainting episodes. […] Prolonged standing or sudden upright posture changes are the most frequent vasovagal syncope triggers. Being upright strains veins in the legs to push blood back to the heart. As blood pools in the abdomen and limbs, input signals the nervous system to maintain stable blood flow to the brain. However, nervous system dysfunction causes an overreaction, causing the heart rate to slow and vessels to dilate, dropping blood pressure. This often causes kids to faint upon standing or leaving the bed.

• #21 Vasovagal Syncope: Symptoms, Causes, and Treatments

  https://resources.healthgrades.com/right-care/heart-health/vasovagal-attack

  Vasovagal syncope episodes cause a rapid drop in heart rate and blood pressure due to autonomic dysfunction, resulting in decreased blood flow to the brain and fainting. […] Vasovagal syncope is the most common cause of fainting. […] A vasovagal syncope episode may occur in a person of any age, but they are more common in children, young adults, and older adults. […] Scientists are not entirely sure what causes vasovagal syncope episodes, but they believe that genetics may play an important role. […] The following situations can trigger a vasovagal syncope episode: Standing: Prolonged standing is associated with vasovagal syncope episodes because blood may pool in the legs, reducing blood flow to the brain. […] Heat exposure: Heat exposure can also lead to a vasovagal syncope episode.

• #21 Vasovagal Syncope: Symptoms, Causes, and Treatments

  https://resources.healthgrades.com/right-care/heart-health/vasovagal-attack

  Emotions: Heightened emotions, such as panic or fright — including that felt when seeing blood, having blood drawn, or being fearful for your life — may cause a vasovagal syncope episode. […] Straining: Straining to have a bowel movement can result in a vasovagal syncope episode from the stimulation of the vagus nerve, which lowers the heart rate in some people. […] Exercise: Another cause of vasovagal syncope episodes is the rapid pooling of blood in the leg muscles after running or doing other strenuous exercises.

• #22 Syncope: Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/811669-overview

  Situational syncope is essentially a reproducible vasovagal syncope with a known precipitant. Micturition, defecation, deglutition, tussive, and carotid sinus syncope are types of situational syncope. These stimuli result in autonomic reflexes with a vasodepressor response, ultimately leading to transient cerebral hypotension. These are not life-threatening but can cause morbidity. The treatment involves avoidance of the precipitant when possible and the initiation of counter maneuvers when anticipated. […] Syncope due to orthostatic hypotension can occur through several mechanisms. Pure autonomic failure can be associated with Parkinson disease or dementia. Secondary autonomic insufficiency can be due to diabetes, uremia, or spinal injury. Drugs such as alcohol cause orthostatic intolerance, and medications such as vasodilators and antidepressants block orthostatic reflexes. Volume depletion due to blood loss, vomiting, diarrhea, poor oral intake, and diuretics also causes orthostatic syncope.

• #22 Syncope: Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/811669-overview

  Reflex (neurally mediated) syncope may be due to vasovagal syncope, which is mediated by emotional distress such as fear or physical pain. Situational syncope describes syncope that occurs with a fixed event such as micturition, deglutition, exercise induced, and carotid sinus syncope. These causes tend to be more benign and do not predict poor outcomes. […] Vasovagal syncope is the most common type in young adults but can occur at any age. It usually occurs in a standing position and is precipitated by fear, emotional stress, or pain (eg, after a needlestick). Autonomic symptoms are predominant. Classically, nausea, diaphoresis, fading or „graying out” of vision, epigastric discomfort, and light-headedness precede syncope by a few minutes. The syncope is thought to occur secondary to efferent vasodepressor reflexes by a number of mechanisms, resulting in decreased peripheral vascular resistance. It is not life-threatening and occurs sporadically.

• #22 Syncope: Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/811669-overview

  Dehydration and decreased intravascular volume contribute to orthostasis. Orthostatic syncope describes a causative relation between orthostatic hypotension and syncope. Orthostatic hypotension increases in prevalence with age as a blunted baroreceptor response results in failure of compensatory cardioacceleration. In elderly patients, 45% of these cases are related to medications. Limited evidence suggests that polydipsia may reduce recurrences. Orthostasis is a common cause of syncope and tends to be recurrent. Bedside orthostatics cannot exclude this as an etiology; if it is suspected, patients should be referred to a primary care provider for outpatient tilt-table testing.

• #22 Syncope: Practice Essentials, Background, Pathophysiology

  https://emedicine.medscape.com/article/811669-overview

  Cardiac (cardiopulmonary) syncope may be due to vascular disease, cardiomyopathy, arrhythmia, or valvular dysfunction and predicts a worse short-term and long-term prognosis. Obtaining an initial electrocardiogram (ECG) is mandatory if any of these causes are possible for the differential diagnosis. […] The American College of Cardiology (ACC), American Heart Association (AHA), and Heart Rhythm Society (HRS) guidelines indicate short-term risk factors (30 days) include male sex, age older than 60 years, palpitations occurring before loss of consciousness, exertional syncope, heart failure, structural heart disease, cerebrovascular disease, family history of sudden cardiac death, and trauma, as well as some physical evaluation or laboratory anomalies (evidence of bleeding, persistent abnormal vital signs, abnormal electrocardiogram [ECG], positive troponin level).

• #23 Table: Some Causes of Syncope-Merck Manual Professional Edition

  https://www.merckmanuals.com/professional/multimedia/table/some-causes-of-syncope

  Vasovagal (neurocardiogenic) […] Increased intrathoracic pressure (eg, tension pneumothorax, cough, straining to urinate or defecate, Valsalva maneuver) […] Warning symptoms (eg, dizziness, nausea, sweating); recovery usually prompt but not immediate (5 to 15 minutes) although can be prolonged in rare cases […] Precipitant usually apparent […] Strong emotion (eg, pain, fear, sight of blood) […] Warning symptoms (eg, dizziness, nausea, sweating); recovery prompt but not immediate (5 to 15 minutes, but sometimes up to hours) […] Precipitant usually apparent […] Carotid sinus pressure […] Warning symptoms (eg, dizziness, nausea, sweating); recovery prompt but not immediate (5 to 15 minutes, but sometimes up to hours) […] Precipitant usually apparent (eg, turning head, button collar, shaving) […] Swallowing (rare) […] Warning symptoms (eg, dizziness, nausea, sweating); recovery prompt but not immediate (5 to 15 minutes, but sometimes up to hours) […] Precipitant usually apparent.

• #24 Fainting (Syncope): Causes, Symptoms, Treatment, Prevention

  https://www.medicinenet.com/fainting/article.htm

  Vasovagal syncope is one of the most common causes of fainting. In this situation, the balance between the chemicals adrenaline and acetylcholine is disrupted. Adrenaline stimulates the body, including making the heart beat faster and blood vessels narrower, thereby increasing blood pressure. Acetylcholine does the opposite. When the vagus nerve is stimulated, excess acetylcholine is released, the heart rate slows and the blood vessels dilate, making it harder for blood to defeat gravity and be pumped to the brain. This temporary decrease in blood flow to the brain causes the fainting episode. […] Pain can stimulate the vagus nerve and is a common cause of fainting (vasovagal syncope). Other noxious stimuli can do the same thing, including situational stressors. Commonly, medical and nursing students faint when observing their first operation, autopsy, or when a person or someone else is bleeding. Some people pass out when they hear bad news; others pass out when they experience the sight of blood or needles. In the Victorian age, this was known as a „swoon.” […] Other situations commonly cause the heart rate to temporarily slow and cause a faint. Straining with urination, bowel movement, or coughing can cause a vagal response, increase acetylcholine levels and decrease blood flow to the brain.

• #25 Syncope: epidemiology, etiology, and prognosis

  https://pmc.ncbi.nlm.nih.gov/articles/PMC4258989/

  Initial therapy of vasovagal syncope is non-pharmacological. […] If failure of initial recommendations, the next step is pharmacological treatment with the use of fludrocortisone if vasodepressor response. […] The causes are structural heart diseases or conditions that result in decreased cardiac output such as aortic stenosis, hypertrophic cardiomyopathy, ischemic heart disease, heart failure, aortic dissection, cardiac tamponade, prosthetic valve thrombosis, cardiac tumors, pulmonary hypertension, pulmonary embolism etc. […] Orthostatic or postural hypotension (OH) presents as falls, dizziness, or syncope, resulting in functional impairment, with head injury, bone fractures and hospitalization. […] It is more common in the elderly, with frequency rates of up to 55% in those that residing in institutions, and with prevalence of 12%.

• #26 Syncope: Medications as Cause and Contributing Factors

  https://www.uspharmacist.com/article/syncope-medications-as-cause-and-contributing-factors

  Syncope is suspected to occur secondary to efferent vasodepressor reflexes by a number of mechanisms; decreased peripheral vascular resistance ensues. This type of syncope is not life threatening and occurs sporadically. Vasovagal syncope is the most common type in young adults but can occur at any age. The most common triggers of vasovagal syncope in older adults are prolonged standing and vasodilator medication. Some elderly adults are susceptible to syncope secondary to reflex increase in vagal tone caused by situations such as coughing, straining at stool and micturition, which leads to bradycardia and hypotension. Involuntary movements may occur during the brief syncopal period, mimicking a seizure. Although recovery is typically rapid, symptoms of longer duration (e.g., confusion, disorientation, dizziness) can occur in older patients.

• #26 Syncope: Medications as Cause and Contributing Factors

  https://www.uspharmacist.com/article/syncope-medications-as-cause-and-contributing-factors

  In the elderly, modifying or discontinuing medications known to cause syncope is often the only necessary intervention. Seniors with hypertension who take antihypertensive medication and develop syncope (i.e., either orthostatic or vasovagal) present a difficult therapeutic dilemma; individualized therapy is required. Medication management is necessary in patients who experience symptoms without warning, and fludrocortisone has been reported as useful; midodrine can be used either alone or in combination with fludrocortisone but with caution. Serotonin antagonists, such as fluoxetine and sertraline, have been reported to be effective, although further clinical trials need to validate this finding. Adjuvant therapies include elastic support hose, relaxation techniques (biofeedback), and conditioning using repeated head-up tilt as therapy. In some patients who have recurrent syncope due to cardioinhibitory responses, permanent cardiac pacing is beneficial.

• #27 Vasovagal Syncope: Causes, Symptoms, and Prevention Tips – The Kingsley Clinic

  https://thekingsleyclinic.com/resources/vasovagal-syncope-causes-symptoms-and-prevention-tips/

  Vasovagal syncope is a type of reflex syncope, triggered by a reflex response that affects the heart and blood vessels. When activated, the nervous system sends signals that slow the heart rate and widen the blood vessels. This results in a sudden drop in blood pressure, reducing blood flow to the brain and causing fainting. […] Certain lifestyle factors can increase the likelihood of experiencing vasovagal syncope. Standing for extended periods, especially in hot environments, can cause blood to pool in the legs, reducing blood flow to the brain. Dehydration is another common trigger, as it lowers overall blood volume. Emotional stress, such as anxiety or fear, can also activate the reflex that leads to fainting. […] Some medical conditions can heighten the risk of vasovagal syncope. For instance, individuals with low blood pressure (hypotension) are more prone to fainting because their circulatory system may already be compromised. Certain heart conditions, such as arrhythmias (irregular heartbeats), can also contribute to fainting episodes.

• #27 Vasovagal Syncope: Causes, Symptoms, and Prevention Tips – The Kingsley Clinic

  https://thekingsleyclinic.com/resources/vasovagal-syncope-causes-symptoms-and-prevention-tips/

  There is evidence suggesting that some individuals may have a genetic predisposition to vasovagal syncope. If you have a family history of fainting, you may be more likely to experience it yourself. […] Fainting is the hallmark symptom of vasovagal syncope, occurring in nearly all cases. It is caused by a sudden reduction in blood flow to the brain, leading to a temporary loss of consciousness. Fainting episodes are usually brief, lasting less than a minute, and are often triggered by prolonged standing, dehydration, or emotional stress. […] Fludrocortisone is a corticosteroid that helps the body retain sodium, which increases blood volume and helps prevent sudden drops in blood pressure. It is often prescribed for vasovagal syncope to help stabilize blood pressure. […] Midodrine is a vasopressor that works by tightening blood vessels, which raises blood pressure and helps prevent fainting. It is commonly used for patients with low blood pressure related to vasovagal syncope.

• #27 Vasovagal Syncope: Causes, Symptoms, and Prevention Tips – The Kingsley Clinic

  https://thekingsleyclinic.com/resources/vasovagal-syncope-causes-symptoms-and-prevention-tips/

  Beta-blockers, such as metoprolol, work by slowing the heart rate and reducing the force of heart contractions. This helps prevent the sudden drop in heart rate and blood pressure that can lead to fainting in vasovagal syncope. […] SSRIs, a class of antidepressants, can help regulate the autonomic nervous system, which controls involuntary functions like heart rate and blood pressure. They are sometimes used to treat vasovagal syncope, particularly in patients whose episodes are triggered by anxiety or emotional stress. […] A pacemaker is a small device implanted under the skin that helps regulate the heart’s electrical activity. It is sometimes used to treat vasovagal syncope by preventing sudden drops in heart rate that can lead to fainting.

• #28 Syncope (Fainting) | American Heart Association

  https://www.heart.org/en/health-topics/arrhythmia/symptoms-diagnosis–monitoring-of-arrhythmia/syncope-fainting

  Cardiac syncope is a higher risk in men and those over age 60. […] Patients with VVS and without a serious medical condition usually can be managed in an outpatient setting. […] When it comes to driving after a syncope episode, there are no restrictions for VVS patients who had no fainting spells in the previous year.

• #29 Isolated vasovagal and vasovagal disease

  https://www.escardio.org/Journals/E-Journal-of-Cardiology-Practice/Volume-5/Isolated-Vasovagal-and-Vasovagal-disease-Title-Isolated-Vasovagal-and-Vasova

  In subjects in whom VVS starts in old age, loss of consciousness cannot be regarded as an isolated manifestation, as it is frequently associated not only to cardiovascular or neurological diseases, but also to other dysautonomic disturbances, such as carotid sinus hypersensitivity, post-prandial hypotension, progressive orthostatic hypotension and symptoms of autonomic dysfunction. […] Even though VVS starting in old age shares the same pathophysiological mechanism of hypotension bradycardia with isolated VVS both during head-up tilt test and during documented spontaneous syncope, these findings should be regarded as an expression of a pathological process mainly related to a generalised involvement of the autonomic nervous system or, more in general, to aging processes. […] The classification of the causes of syncope used by the Task Force on syncope of the European Society of Cardiology includes some forms of non-classical VVS which are diagnosed on the basis of minor clinical criteria, exclusion of other causes of syncope (absence of heart disease) and positive response to head-up tilt test.

• #29 Isolated vasovagal and vasovagal disease

  https://www.escardio.org/Journals/E-Journal-of-Cardiology-Practice/Volume-5/Isolated-Vasovagal-and-Vasovagal-disease-Title-Isolated-Vasovagal-and-Vasova

  With vasovagal susceptibility probably present in all healthy humans, isolated VVS is a physiological phenomenom. […] Isolated vasovagal syncope (VVS) is not a disease, but rather, the clinical manifestation of an autonomic reflex predisposed in all (or almost all) individuals. […] Why certain subjects appear to be more susceptible than others to the development of paradoxical hypotension and bradycardia, and why the event occurs at one time and not another, remains largely unknown. […] Isolated VVS should be distinguished from vasovagal disease, in which VVS appears as an expression of a pathological process, mainly related to a generalised involvement of the autonomic nervous system. […] It is known that clinical manifestations of VVS change significantly in older subjects and that medical history has a limited value in establishing the cause of syncope in older people.

• #29 Isolated vasovagal and vasovagal disease

  https://www.escardio.org/Journals/E-Journal-of-Cardiology-Practice/Volume-5/Isolated-Vasovagal-and-Vasovagal-disease-Title-Isolated-Vasovagal-and-Vasova

  In general, the behavior of blood pressure during the first minutes of head-up tilt test before the beginning of vasovagal reaction is similar in VVS subjects and in control subjects without a history of fainting. […] Many hormonal factors, such as serotonine, adrenaline, arginine vasopressin, -endorphins, adenosine and galanin have been supposed to have a role in eliciting VVS. However, a causal role of these hormonal factors and an abnormality of hormonal function – has never been definitely demonstrated. […] To conclude, Isolated VVS seems to be not a disease, but rather the clinical manifestation of an autonomic reflex predisposed in all (or almost all) individuals.

• #30 Vasovagal Syncope: Symptoms, Diagnosis, Treatments – SelfDecode Health

  https://health.selfdecode.com/blog/vasovagal-syncope/

  Vasovagal syncope occurs by the activation of a heart reflex (hypotension/bradycardia reflex) through the stimulation of the vagus nerve. This reflex causes a rapid decrease in heartbeat and widening of blood vessels. […] Many mechanisms have been suggested to cause fainting episodes, but these factors and their relative contributions are still not fully understood. […] In a clinical trial on 23 children and adolescents (7-18 years), those with vasovagal syncope had significant imbalances in the involuntary control of their body (autonomic nervous system). They had decreased sympathetic (fight-or-flight) and increased vagal tone. These imbalances may be more severe for adolescents. […] In a clinical trial on 29 people with syncope induced by the tilt table test, images of their hearts revealed a sudden loss of blood flow into the heart, possibly decreasing blood outflow moments before fainting.

• #31 Presyncope: What It Is, What Causes It, How It Is Treated, and More

  https://www.webmd.com/hypertension-high-blood-pressure/what-is-presyncope

  Cardiac presyncope or syncope can be caused by problems with a pacemaker. They might also indicate a tear in the large artery that carries blood to the rest of your body. A narrowing of the valve between your aorta and heart might also cause you to feel faint. […] Neurologic presyncope can be caused by conditions such as a stroke or seizure. It can also result from a transient ischemic attack (TIA), which is a brief stroke that only lasts a few minutes. Other, less common causes of neurologic presyncope include migraines and normal pressure hydrocephalus (NPH), which is a type of brain disorder. […] Postural orthostatic tachycardia syndrome (POTS). This is a rare disorder that affects your blood flow. It most commonly occurs in women from ages 13 to 50. It happens when your heart rate increases by at least 30 beats per minute when you stand. It causes other symptoms when you stand such as presyncope and tiredness.

• #32 Syncope: Evaluation and Differential Diagnosis | AAFP

  https://www.aafp.org/pubs/afp/issues/2017/0301/p303.html

  Syncope is classified as cardiac, neurally mediated (reflex), and orthostatic hypotension. The differential diagnosis should include nontraumatic causes of transient loss of consciousness. Rare causes include subclavian steal syndrome, pulmonary embolism, acute myocardial infarction, acute aortic dissection, leaking aortic aneurysm, subarachnoid hemorrhage, and cardiac tamponade. […] Neurally mediated syncope is the most common type, comprising approximately 45% of cases. It can be vasovagal, situational, or secondary to carotid sinus hypersensitivity. The pathophysiology is complex, consisting of an interaction between autonomic systems paradoxically favoring parasympathetic or vagal tone, which causes bradycardia and hypotension. […] Cardiac syncope occurs in approximately 20% of syncope presentations. It is most often caused by an arrhythmia, and less often by a structural cardiac abnormality. In a prospective cohort study, patients with cardiac syncope had a twofold increase in mortality over 17 years. The presence of cardiovascular disease predicts a cardiac etiology of syncope with 85% to 94% sensitivity and 64% to 83% specificity.

• #32 Syncope: Evaluation and Differential Diagnosis | AAFP

  https://www.aafp.org/pubs/afp/issues/2017/0301/p303.html

  Patients with syncope who are at low risk of adverse events (e.g., those with symptoms consistent with vasovagal or orthostatic hypotension syncope, no history of heart disease, no family history of sudden cardiac death, and normal electrocardiographic findings) may be safely followed without further intervention or treatment.

• #33 Syncope (Fainting)

  https://www.rwjbh.org/treatment-care/heart-and-vascular-care/diseases-conditions/syncope-fainting-/

  Vasovagal syncope. The most common type of syncope. Occurs when you faint because your body overreacts to certain triggers, such as the sight of blood, extreme emotional distress, dehydration, anxiety, pain, hunger, etc. […] Syncope is a symptom that can be due to several causes. Many non-life-threatening factors, such as overheating, dehydration, heavy sweating, exhaustion or the pooling of blood in the legs due to sudden changes in body position, can trigger syncope. However, certain conditions, traits or habits may also raise your risk for syncope. […] Other conditions that contribute to syncope: Coronary artery disease, Heart arrhythmias.

• #34 Reflex syncope in adults and adolescents: Clinical presentation and diagnostic evaluation – UpToDate

  https://www.uptodate.com/contents/reflex-syncope-in-adults-and-adolescents-clinical-presentation-and-diagnostic-evaluation

  Vasovagal syncope is the most common cause of syncope in patients of all ages, and its diagnosis may usually be made by taking a careful history detailing the features of symptomatic events and identifying well-known triggers; however, a classic history is not always present, especially in older individuals. […] Acute vasovagal reactions leading to syncope or presyncope are also common in a number of potentially stressful settings, such as blood donation or emotional upset. […] Even among patients with structural heart disease, especially if electrophysiology testing is nondiagnostic, approximately 60 percent of syncope episodes are reflex in origin. […] Understanding the pathophysiology involved in reflex syncope is essential to understanding its clinical manifestations and prevention strategies. […] The potential neurohumoral events that participate in vasovagal reactions are complex and remain poorly understood; better understanding may be expected to lead to more specific therapeutic strategies in the future.

• #35 VASOVAGAL SYNCOPE AND CHRONIC VAGAL EXCESS – Dr. Nicholas L. DePace, M.D., F.A.C.C.

  https://franklincardiovascular.com/vasovagal-syncope-and-chronic-vagal-excess/

  A tilt test is extremely helpful in reproducing the symptoms and disclosing the mechanism of Vasovagal Syncope and PS testing may document the mechanism as well without requiring all of the symptoms to be demonstrated. […] Vasovagal Syncope is a benign problem and has a good prognosis. […] One has to consult their physician if they have frequent episodes of what they believe is Vasovagal Syncope for proper treatment and oftentimes if it is quite profound, they will need to seek the results of an Autonomic physician specialist.

• #36 Diagnosing and Treating Vasovagal Syncope | Banner Health

  https://www.bannerhealth.com/services/heart/vasovagal-syncope

  If youre still having symptoms after adjusting your lifestyle, your provider may recommend: prescribed medications may help regulate blood pressure or heart rate. […] If a slow heart rate (bradycardia) is causing vasovagal syncope, your provider may recommend a pacemaker to maintain your heart rate and prevent fainting episodes. However, its rare to need a pacemaker for vasovagal syncope.

• #37 Vasovagal Syncope – Melbourne Heart Group

  https://www.melbourneheart.com.au/for-patients/vasovagal-syncope/

  Being able to recognise early warning symptoms is crucial in controlling or preventing a full syncope episode. […] VVS is characterized by the pooling of blood in the peripheral areas of the body, triggering the symptoms. […] In the majority of cases, medical interventions are not necessary and are not recommended as the initial approach for VVS. […] Additional cardiac conditions related to autonomic dysfunction include inappropriate sinus tachycardia (IST) and postural orthostatic tachycardia syndrome (POTS). […] The recommendation of a pacemaker for VVS is relatively rare. […] The long-term outlook is positive in people with VVS.

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