What is Neurocardiogenic Syncope?

Jul 28

Neurocardiogenic Syncope, also known as Vasovagal Syncope, occurs when someone loses consciousness because of their body overreacting to a trigger such as the sight of blood or extreme emotional distress. It is also referred to as neurocardiogenic syncope (1)

How common is Neurocardiogenic Syncope?

Syncope, also known as fainting, is a common condition. It is the most common form of dysautonomia. Syncope is a symptom, not a disease, and is classified according to the underlying cause. It can occur in response to a neurological, metabolic, psychiatric, or cardiac problem.

Neurocardiogenic syncope is the most common form of syncope. It is a benign condition. It affects 3% of men and 3.5% of women at some point in life. Syncope is more common as you get older, affecting up to 6% of people over age 75. Vasovagal syncope can occur at any age, and occurs in people with and without other medical problems (2).

What Causes Vasovagal Syncope?

Vasovagal syncope occurs due to a failure of autonomic nervous system control. This occurs in response to a trigger of some kind, leading to an exaggerated autonomic nervous system response. This decreases blood flow to the brain and causes a fainting attack (9).

What is the Autonomic Nervous System?

The autonomic nervous system, or ANS, controls the body’s unconscious vital functions. These include things like regulation of blood pressure, heart rate, digestion, respiration, and sexual function. It has two divisions, the sympathetic and parasympathetic systems.

The sympathetic system functions as part of the stress response, and when fired will increase heart rate and blood pressure, and shunt blood towards muscles and away from the skin. It is often described as the “fight or flight” mechanism.

The parasympathetic system does the opposite. It decreases heart rate and blood pressure, and promotes functions of the gastrointestinal tract. It is often called the “resting-digesting” system.

Both of these systems are constantly working together to regulate appropriate heart rate, blood pressure, responses to stress, and many other important functions.

When seated or standing, gravity pulls blood down towards the feet. A normally functioning autonomic nervous system will adjust blood pressure, heart rate, and muscle tone to keep blood flowing to the brain (10).

What Happens in Neurocardiogenic Syncope?

When someone experiences neurocardiogenic syncope, a trigger stimulus of some kind leads to an inappropriate response from the ANS. There is a sudden large increase in output from the parasympathetic system, which causes blood vessels to dilate. This reduces filling of the heart and decreases blood pressure, so less blood is pumped to the brain. At the same time, the ANS output causes the heart rate to slow down, which further decreases blood flow to the brain. Ultimately this leads to syncope, and the person loses consciousness (11).

What are Symptoms of Vasovagal Syncope?

Someone who is approaching an episode of vasovagal syncope may experience paleness of skin, lightheadedness, nausea, tunnel-vision, changes of body temperature (such as feeling cold or hot), clammy sweating, and blurred vision. Once the vasovagal syncope episode takes place, people around you may notice abnormal movement patterns, slowing or weak pulse, and dilated pupils.

Recovery after a vasovagal episode generally begins in less than a minute. However, if you stand up too soon after fainting — within about 15 to 30 minutes — you're at risk of fainting again.

What Happens in the Nervous System with Vasovagal 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.

An important heart reflex is also involved in the process. The heart contains nerves known as Cardiac C Fibers. These function as a braking mechanism to prevent the heart from beating too fast or contracting too hard. When they are stimulated, they fire up to the medullary vasodepressor system, which then fires to slow the heart back down and cause heart muscles to relax.

The vasodepressor system receives input from many parts of the brain and body. These varied inputs create a number of different presentations, collectively known as Neurally Mediated Reflex Syncopal Syndromes.

What are the Different Presentations of Vasovagal Syncope?

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. This can be triggered by pain, or following exercise.

In Carotid Sinus Syncope, specialized nerves in the carotid arteries of the neck called baroreceptors are stimulated by things like turning the head, shaving, tight shirt collars, or massaging the front of the neck. This stimulates the vasodepressor system, which has an exaggerated output and provokes syncope.

In Situational Syncope, the trigger can be something as trivial as coughing, sneezing, swallowing, urinating, or having a bowel movement. These processes normally stimulate receptors in the lungs, heart, bladder, and digestive tract. They fire up through the Vagus nerve to stimulate the vasodepressor system, which again fires too hard and causes syncope.

In Glossopharyngeal and Trigeminal Neuralgia Syncope, throat or facial pain stimulates these nerves. They fire into the brainstem and stimulate the vasodepressor system, which fires excessively and causes syncope (3).

What are the Consequences of Vasovagal Syncope?

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 (12).

How is Vasovagal Syncope Diagnosed?

Testing for vasovagal syncope starts with a cardiology evaluation to rule out structural heart disease and abnormal heart rhythms. Once these have been ruled out, a tilt table test is usually performed, where patients are taken from lying to vertical positions on a motorized table. People living with neurocardiogenic syncope will show an abrupt decrease in heart rate, blood pressure, or both when the table brings them upright (13).

Vasovagal syncope is usually treated with education. Patients are trained to lay down and elevate their legs when they feel an episode coming on, and are taught to recognize their triggers and avoid situations that may provoke syncope (14).

Medication management can be helpful in some circumstances of vasovagal syncope. Mididrine is also often employed to increase blood vessel tone. SSRI antidepressants may be helpful for some patients, and Fludrocortisone to increase blood volume may help others. All of these strategies come with the potential for unwanted side effects.

How is the NeuroRescue Program different?

The NeuroRescue program strives to directly address the inappropriate neurological reflexes that are creating your neurocardiogenic syncope. We use advanced neurodiagnostic testing to precisely quantify the function of all of the brainstem, cortical, cerebellar, and baroreceptor systems involved in the promotion of your unique syncopal presentation. We use these insights to tailor a precise protocol of rehabilitative exercises and neurostimulation to help you control your syncope and get back to doing the things that you love.

One of the main things your brain does, and maybe even the primary thing, is help you determine where you are in the world. Your brain uses inputs from your inner ear to figure out where your head is in relation to gravity and how it is moving. It uses inputs from your muscles and joints to figure out where your body is in relation to your head and what your body is doing. It uses inputs from your eyes to figure out where your body is in relation to the visual environment.

Your brain needs to put all of that together to make sense of where the world is, and where you are in relation to the world. It needs to be able to localize you effectively in the environment, in order for you to be able to respond to the environment properly.

Your brain organizes all of this information in terms of maps. There is a vestibular map from the inner ear, a proprioceptive map from muscles and joints, a vascular map of your blood flow, a visual map of the world from your eyes, and several others. Your brain needs these maps to be saying largely the same thing about where you are in the world at all times.

One often overlooked feature of neurocardiogenic syncope is that these maps usually fail to match. Your eyes, inner ear, and muscles are creating maps that say different things about where your head is in relation to gravity. When you go from lying down to sitting up or standing, problems in these maps can make it difficult for the brain to compensate for the postural shift. If the brain does not understand the position of the head in relation to gravity, it cannot properly control the vascular system to send the appropriate amount of blood to the head (15). We utilize eye movements to activate the various cortical, subcortical and brainstem regions involved in the ANS to improve function and connectivity (16).

This is why many patients fail to fully resolve their neurocardiogenic syncope with most forms of treatment. Without addressing the problems in these maps, it will remain impossible for the brain to properly control blood flow, and the best they can hope for is to gain some control over their symptoms. We would much rather try to address the underlying cause. Our therapies are target towards first restoring appropriate visual, vestibular, and proprioceptive maps. Once these are working well individually, we retrain your system against different gravitational vectors so you can begin to control your autonomic system properly again. This approach gives us our best hope to resolve your hypotension so you can get back to living the life you deserve.

How Does the NeuroRescue Program Work?

We design your unique NeuroRescue Program to be among the most comprehensive diagnostic and therapeutic protocols available today. We create individual NeuroRescue Programs based on a comprehensive analysis of every relevant neurological system and pathway, using gold-standard, cutting edge neurodiagnostic technologies and examination procedures and state-of-the-art therapies.

We begin with your Discovery Day, wherein we perform a comprehensive history of not only your condition but your life on a timeline. This allows us to dive deeply into your case and see all of the factors that led to where you are now. It helps us uncover hidden problems and associated conditions that may be making it difficult for you to move your recovery forward.

Our examination allows us to identify the areas and pathways of your brain that are involved in your unique syncopal presentation. We begin by precisely quantifying the function of your visual, vestibular, and proprioceptive systems through computerized analysis of your eye movements, your inner ear reflexes, and your balance in a host of different sensory conditions.

We employ technologies including Videooculography and Saccadometry to measure several classes of eye movements. We use Video Head Impulse Testing to measure the function of your inner ear, and Computerized Dynamic Posturography to assess your balance in different sensory conditions.

We use NeuroSensoryMotor Integration testing to evaluate hand-eye coordination and cognition, and Virtualis testing to assess dynamic eye-tracking and perception of vertical in a virtual reality environment.

We combine all of this with a comprehensive physical and neurological examination of your sensory, motor, autonomic, and cognitive systems. We review any relevant laboratory testing, radiological imaging, and prior neurodiagnostic testing, and integrate that information with our findings.

We use this information to identify which parts of your brain are working properly, which systems are struggling, and the precise point at which your systems fatigue.

We can then design a NeuroRescue Program that is unique and specific to your brain and yours alone. Your NeuroRescue Program works to rejuvenate and reintegrate the damaged neurons and pathways in your brain. It works to improve energy, endurance, and functional capacity within your fragile systems.

Our therapies may range from specific eye exercises (4), to specific types of vestibular therapy (5), to unique forms of electrical stimulation (6). We may employ laser and LED photobiomodulation (7), or even exercises in a virtual reality environment (8). All of our therapies will be specific to your unique case, based purely on your neurodiagnostic testing data and examination findings.

We use our technologies and procedures to not only see what we need to address but also when it is time to stop and let you rest. We address your impaired neurological function from multiple angles of therapy and provide metabolic support to improve neurological recovery.

While we cannot bring back neurons that have been lost, your NeuroRescue Program allows us to take the pathways that remain and maximize their efficiency and endurance. And by focusing on the integration of systems, we can do more than just get pathways working better, we can get them working together again. This gives us our best opportunity to return you to living a healthy, vibrant, and fulfilling life.

Your Next Best Step:

Living with vasovagal syncope can be challenging, but there is hope for controlling the condition. To see if the NeuroRescue Program is right for you, contact one of our patient care coordinators to schedule your Discovery Day.

And remember, it’s never too late to start getting better.