Vasovagal Syncope is a sudden, brief loss of consciousness (fainting) caused by decreased blood flow to the brain.
But, what in the world would cause you to just pass out for no reason at all?
Vasovagal Syncope happens when, due to a reflex, the blood vessels in the legs suddenly become larger (dilate), causing a large volume of blood to pool in the legs.
➡ In turn, often the heart rate slows down, the blood pressure drops and you faint.
The vagus nerve is the longest, and one of the most important, nerves in the body.
➡ It starts in the brain stem and extends down, through the neck and into the chest and abdomen.
While there are actually two vagus nerves (the left and the right), doctors usually refer to them together as “the vagus nerve.”
- The vagus nerve helps control several muscles of the throat and voice box.
- It also supplies the heart, lungs, major blood vessels of the chest, and the gastrointestinal tract.
- It plays an important role in regulating the heart rate and keeping the gastrointestinal tract in working order.
- It also carries sensory information from the internal organs back to the brain.
- It’s responsible for the gag reflex (and the cough reflex), slowing the heart rate, controlling sweating, regulating blood pressure, stimulating the contractions of the gastrointestinal tract, and controlling the tone of your blood vessels.
Minutes before you faint (due to vasovagal syncope) you may experience the following:
- Pale skin
- Tunnel vision — your field of vision narrows so that you see only what’s in front of you
- Feeling warm
- A cold, clammy sweat
- Blurred vision
Your family or bystanders may see:
- Jerky, abnormal movements
- A slow, weak pulse
- Dilated pupils
What Triggers It?
For most people, the dilation of blood vessels is triggered by the loss of consciousness. For others, it’s related to the slowing of the heart rate.
- Some of the most common triggers are pain, having your blood drawn or just being exposed to the sight of blood.
- Difficulty urinating or having a bowel movement, coughing, having trouble or pain when swallowing, getting bad news, a sudden fright or standing still for a long time may also trigger the fainting.
It almost always happens when the victim is standing or sitting upright (which is when blood pooling in the legs can happen).
Consciousness returns within a few seconds of falling. This is because once on the ground, gravity no longer causes the blood to pool in the legs and the blood pressure improves almost immediately
When somebody passes out, the right thing to do is to get their head down and elevate their legs. Holding them in an upright position is not helpful.
- After an episode of vasovagal syncope, many people will feel terrible for a few hours or even for the next day or two. During this time they may feel extremely tired, be nauseated and dizzy and experience a loss of appetite.
Until these symptoms disappear they have a high risk of fainting again.
Who Gets Vasovagal Syncope?
- It can happen to anyone at any age, but it’s much more common in adolescents and young adults than in older people.
How Is It Diagnosed?
Diagnosis often involves ruling out other possible causes of the fainting — especially heart-related problems. The tests may include:
- Electrocardiogram: This test records the electrical signals your heart produces. It can detect irregular heart rhythms and other cardiac problems.
- Echocardiogram: This test uses ultrasound imaging to view the heart and look for conditions, such as valve problems, that can cause fainting.
- Exercise stress test. This test studies heart rhythms during exercise. It’s usually conducted while you walk or jog on a treadmill.
- Blood tests. Your doctor may look for conditions, such as anemia, that can cause or contribute to fainting spells.
Treatment is unnecessary most of the time. Your doctor may help you identify your fainting triggers and discuss ways you could avoid them.
However, if you’re experiencing this type of syncope often enough to interfere with the quality of your life, your doctor may suggest a number of medications.
Your doctor may recommend ways to decrease the pooling of blood in your legs.
- You may need to increase salt in your diet if you don’t usually have high blood pressure.
- Avoid prolonged standing — especially in hot, crowded places — and drink plenty of fluids.
In very rare cases, inserting an electrical pacemaker to regulate the heartbeat may help some people who haven’t been helped by other treatments.