Vasovagal or neurocardiogenic syncope is a condition that leads to faint because the body overreacts to specific triggers causing the heart rate and blood pressure to drop suddenly.
It is a common condition that reduces blood flow to the brain, causing a short loose of consciousness. Importantly, it affects about 20% of the population. Within this article, you will find answers to some of the most common questions like what it is, what causes this condition, and many others. Before reaching that point, there will be brief explanations about the basic concepts of the disease.
By reading this article, you will obtain critical insights about Neurocardiogenic Syncope, its causes, its diagnosis, and its treatment. Please continue reading to get pearls on this specific topic by the hand of a Doctor.
What is syncope?
Syncope definition comprises a transient loss of consciousness that limits itself. This goes with an inability to remain standing with later spontaneous recovery. Usually, it has a direct correlation with insufficient blood flow to the brain.
Importantly, it has many causes, but the most common is when the blood pressure is too low, and the heart does not pump enough blood. There are several types of syncope, and all of them have different causes, the most common are the following.
- Reflex Syncope
- Cardiac Syncope/Cardiogenic Syncope
- Orthostatic Syncope
- Cerebrovascular Syncope
- Unexplained Syncope
Reflex syncope is a general term that is used to refer to describe types of syncope resulting from a failure in autoregulation of blood pressure. This situation ultimately leads to a decrease in cerebral blood flow resulting in transient loss of consciousness and a syncopal episode. Reflex syncope is also known as neutrally mediated syncope, and it’s the most common cause of fainting. There are three kinds of reflex syncope.
- Vasovagal Syncope: This happens when the body overreacts to a trigger. There are many types of it, including intense pain or distress. This type accounts for approximately 50% of all cases of fainting episodes.
- Situational Syncope: This type of fainting happens when the patient performs specific actions such as laughing, violent coughing (primarily in men), or swallowing.
- Carotid Sinus Syncope: This type of fainting happens when the neck receives pressure, specifically on the carotid artery, blocking the blood flow to the brain. Fainting can occur due to certain neck motions, shaving, or wearing a tight collar.
This type of syncope happens when there is a problem with the heart. If the heart is not working correctly, there is a possibility that the brain does not receive a sufficient amount of blood. According to statistics, cardiac syncope causes approximately 15% of the fainting episodes. Several heart diseases may lead to cardiac syncope. It is essential to know that this can increase the risk of sudden cardiac death.
- Structural heart diseases like ischemic cardiomyopathy (heart infarction), heart valve disorders, and dilated cardiomyopathy.
- Electrical diseases of the heart like cardiac arrhythmia, ventricular tachycardia, and conditions like Brugada Syndrome.
- Other conditions like pulmonary embolism or aortic dissection.
This type of syncope happens when the patient stands up, and there is a sudden drop in blood pressure. The blood loses the ability to go from the legs to the upper body causing venous pooling leading to fainting. This event receives the name of orthostatic hypotension or orthostatic intolerance. However, several conditions may lead to this type of syncope. The following are some of them: dehydration, blood loss, medications, and underlying diseases.
This type of syncope happens when there is a problem with the blood vessels in and around the brain, preventing it from receiving enough blood. It is not a common cause of syncope, but various conditions may lead to it like:
- Injury from cerebrovascular diseases like strokes and aneurysms.
- Basilar arterial disease
- Steal syndrome.
What causes neurocardiogenic syncope?
The neurocardiogenic syncope is a type of reflex syncope, and it is the most common cause of syncope in adults. More than 85% of syncopal events in people younger than forty are attributable to the vasovagal syndrome.
In order to describe the neurocardiogenic syncope, it is very helpful to think about it as a reflex arc. It has a way up (the afferent limb) and way down (the efferent limb).
Although scientists know that the autonomic nervous system mediates vasovagal syncope, they still do not fully understand it. Through the body, some sensors react to the blood pressure changes; these receive the name of cardiopulmonary baroreceptors. Some of them are in the carotid sinus and the aortic arch, both essential arteries of the body.
The resulting mix of the baroreceptors’ activation due to hypovolemia (low levels of circulating blood) often caused by venous pooling, and an external trigger leads to a neurologic response.
On the other hand, the efferent limb transports the neurologic impulse with an increase in the parasympathetic activity, a type of response of the autonomic nervous system. This causes a heart rate decrease that can be profound, with asystole or no heart beating for several seconds.
At the same time, the increase of parasympathetic response leads to a reduction of vascular tone. This causes the blood vessels to become wider.
All of these conditions, low heart rate, and a decrease in the blood’s return to the heart cause a reduction in cardiac output. If there is a decrease in the amount of blood the heartbeats, this will result in low blood pressure.
Usually, the brain can autoregulate these changes. But when the blood pressure becomes too low for the autoregulation to happen, the patient loses consciousness.
What is the difference between neurocardiogenic syncope and vasovagal syncope?
Actually, there is no difference between them. The neurocardiogenic syncope and the vasovagal syncope are the same conditions. The only thing that changes is the name.
It is a disease that receives many names like vasodepressor syncope or vasovagal syndrome. It does not matter the name; the sickness remains the same.
Of course, some of these names are not so common but because they are in disuse. Some of these names are old and were the first names that this condition received before being profoundly studied.
What heart conditions cause syncope?
The heart is the organ in charge of pumping blood to the rest of the body. When the heart fails or has a poor job, many symptoms can arise; syncope is one of the most common.
As a matter of fact, syncope is very common in older adults with heart diseases, with a sharp increase after age 70. These patients are at risk of having recurrent episodes of syncope. It does not matter the nature of the condition, mechanical or electrical; many can lead to this condition.
Among the most common situations, you can find the following:
- Heart failure
- Atrial fibrillation
- Heart infarction
- Heart valve disease
- Dilated cardiomyopathy
- Ventricular Tachycardia
- Brugada Syndrome
Is neurocardiogenic syncope a heart condition?
Although neurocardiogenic syncope is a disease closely related to the heart, it is not classified as a heart condition. The neurocardiogenic syncope is a reflex syncope or neurally mediated syncope that arises from nerves.
Moreover, it is, indeed, a cardiovascular event that ultimately causes the heart to reduce cardiac output. The decrease in the circulating blood because of the venous pooling in the legs directly affects the heart. Therefore, the outcome will be hypotension and fainting.
However, it is not a heart condition per se like arrhythmias or heart infarction. The autonomic nervous system reacts to specific needs within the body, causing the whole event. Hence, the neurocardiogenic syncope is specifically a nervous reflex of the parasympathetic nervous system.
Can stress cause vasovagal syncope?
It depends because it is true that that vasovagal syncope has a nervous component that plays a significant role. Nonetheless, the activation of these events has another element, the external factor.
It is not known yet how this acts on the pathology. But scientists know that several emotional triggers or external components may induce the neurocardiogenic syncope. For example, some people faint when they see blood, which is likely to be a vasovagal syncope.
Everyone is different from each other, and the trigger can be different. Still, all of the triggers converge in a stressful situation that overwhelms the patients. On the other hand, there are people with whom the stress will not affect them, and this can be purely a nervous reflex that arises spontaneously.
What are the symptoms of vasovagal syncope?
Patients may not have any indication that they are going to faint until it happens. However, some people have brief signs that they may be about to faint. The symptoms are the following:
- Looking pale or gray
- Blurry vision
- Bradycardia (low heart rate)
- Getting sweaty palms
- Feeling dizzy or light
- Feelings of warmth
If the patient can lie down at the first sign of these symptoms, it is most likely that the fainting will be prevented. When it happens, this type of fainting almost always happens in a standing position and the patient falls. However, not all of the patients can notice these symptoms before fainting.
These patients usually do not experience chest pain symptoms, as this is most common in cardiac syncope. Lying down helps restore the circulation and blood flow to the brain. Patients usually experience 1 or 2 episodes of vasovagal syncope through their lives without syncope recurrence. For others, the problem can be chronic, and it can become a recurrent vasovagal syncope.
What are the possible complications of vasovagal syncope?
Vasovagal syncope itself is generally not dangerous. Moreover, the sole fact of fainting can be dangerous if it happens at certain times, like while driving or doing another potentially risky activity.
Some patients have recurrent neurocardiogenic syncope that is not under their control, and doctors advise them against driving, especially in patients who do not have any warning signs before they faint. If patients suffer from a heart condition, there is an increased risk of suffering and sudden cardiac death. Still, it is extremely rare for this to happen.
How is neurocardiogenic syncope diagnosed?
To make an assertive diagnosis of vasovagal syncope, the physician must rule out the first other possibilities, like heart-related programs.
The doctor will first review the medical history and perform a complete physical examination. This will include measuring the blood pressure while lying down, seated, and then standing and auscultating the heart. The doctor will also perform or ask for the following exams before tilt table testing:
- Electrocardiogram: The doctor will ask the patient to use a Holter, a portable monitor. This will record the electrical signals the heart produces. It can detect irregular heart rate and other cardiac problems. The patient may need to use this portable device at least for a day to rule out cardiac diseases.
- Echocardiogram: This test uses ultrasound imaging to view the heart and look for conditions such as valve problems that may cause fainting. This examines as well the blood flow within the heart and the heart motion.
- Exercise Stress Test: This test studies the heart rates during exercise. It is a test that is conducted while the patient walks or jogs on a treadmill.
- Blood test: If the doctor suspects an abnormality, he will ask for a blood test. These tests can show results that may lead the doctor to a diagnosis like anemia that can cause or contribute to the recurring syncope.
If no heart problem seems to cause the fainting, the doctor will suggest a tilt table test. It is a test in which someone measures the heart rate and the blood pressure while the patient lays down on a table.
This table will be tilted up and down for some time. Seldom the doctor gives medicine to trigger a fainting response. Nonetheless, if the patient has vasovagal syncope, a faint may occur during the upward tilt.
How is neurocardiogenic syncope treated?
The treatment for vasovagal syncope is very conservative. Usually, these patients present warning signs before fainting like dizziness, nausea, or sweaty palms.
Doctors recommend to these patients to immediately lie down. Tensing the muscles in arms or crossing legs can also help prevent fainting.
Passively raising the legs in the air can also help with hypotension as it allows the blood to return. The doctor will indicate the following recommendations to help with the treatment of the vasovagal syncope:
- Moderate exercise training
- Stop using medications that lower blood pressure like diuretics
- Avoid triggers like stressful situations or standing for too long
- Drink plenty of liquids and keep hydrated to maintain blood volume
- Wearing compression stockings
- Eat a higher salt diet to help control blood volume
There will be some cases in which the doctor may indicate medicine to help control vasovagal syncope. These medications are usually for people with several episodes of fainting or recurrent syncope episodes. These are some of the medicines:
- Alpha-1-Adrenergic agonists to increase the blood pressure, helping with hypotension
- Corticosteroids to help improve the sodium and fluid levels
- Selective serotonin reuptake inhibitors will act directly in the nervous system, helping to moderate the nervous response.
However, there may be refractory neurocardiogenic syncope cases that will be resistant to this type of treatment. The medications will not be effective, and the lifestyle changes will not be effective as well.
Doctors will sometimes try orthostatic training to increase the amount of time spent upright. But in cases where there is a significantly slower rate of the heartbeat, a heart pacemaker implantation may be the answer.
Are you having episodes of it?
This tool is a vasovagal symptoms checker. It gathers the most important signs, symptoms, and risk factors for this condition. Therefore, it would help anyone who uses it to determine the likelihood of having vasovagal syncope. Besides, the tool is free to use and would only take a few minutes.