What is Reflex Mediated Syncope?

Reflex Mediated Syncope(Vasovagal syncope, neurocardiogenic syncope) may be referred to by many names including the common faint, vasovagal syncope or neurocardiogenic syncope. Syncope means a brief loss of consciousness. Syncope can be caused by many things, but reflex syncope is the most common type. This is not a heart condition, but occurs when your autonomic nervous system causes a drop in your heart rate and/or blood pressure. The autonomic nervous system controls many of your bodily functions without you having to think about them, such as your breathing, your heartbeat, and sweating.

A number of different triggers such as fright, intense emotion or exercise can cause a syncopal episode. The most common cause is pooling of blood in the lower half of the body, such as after you have been sitting or lying down for a long period of time. When you stand up, the pooled blood does not immediately return to the heart; this sends a signal to your autonomic nervous system to release hormones like adrenaline, which initially increases your blood pressure and heart rate. However, in response to this “burst of adrenaline”, another part of your autonomic nervous system (the parasympathetic nervous system) lowers your heart rate and blood pressure. This leads to loss of consciousness or fainting. Once you faint, the heart rate and blood pressure quickly increase to normal levels, although they may remain a little bit low for a few hours. It is common to faint immediately after exercise; fainting while still doing the activity is unusual and warrants further investigation.

Effects and Symptoms

It is common for your vision to go blurry, for you to have abdominal pain, heart palpitations or nausea before fainting. It is also common for others to observe some stiffening or seizure-like activity while you are unconscious. It is common to feel tired after fainting.

Diagnosis

A good clinical history and physical examination is all that is needed to make a diagnosis of Reflex Mediated Syncope. There is no need for special testing.

Management and Treatment

Here are some simple suggestions to decrease your chances of fainting:

1. Avoid standing or sitting in one position for a long period of time without changing position. Avoid long hot showers, saunas and hot tubs.
2. Get up gradually. For example, instead of jumping out of bed rapidly, sit up first, do a few exercises and then stand up. 
3. Exercises such as placing your elbows out to the sides, interlocking your fingers and pulling to stretch your arms or crossing your legs and squeezing your knees together (as though trying to squeeze a coin between your kneecap and the back of your leg) can help when sitting or standing for a long time.
4. If you experience any of the warning symptoms of syncope such as visual disturbances or light-headedness, it is important to put your head down. This may prevent you from fainting. 
5. Increase your fluid intake with fluids such as milk, electrolyte drinks, tomato juice, or other salt-containing fluids. This increases the blood pressure and decreases the likelihood of fainting. Simply drinking water may not be beneficial. Avoid beverages that contain caffeine such as coffee, tea and energy drinks.
6. Small, frequent, healthy snacks are often helpful.
7. Increase your salt intake by adding salt to healthy foods rather than increasing your intake of unhealthy fatty foods that have a high salt content. An increase of approximately 1 gram of salt per day is helpful. This is less than ½ teaspoon per day.
8. Do not skip breakfast.
9. Continue to be active, but ensure that you have an adequate warm-up and cool down before and after activities.
10. Continue to exercise your legs to increase the muscle tone in your legs. This helps the blood return quickly to your heart.

If you have another similar type of fainting episode that does not result in an injury, it is not necessary to go to the hospital or call 911. If there are concerns that the episode occurred during an activity (before you have a chance to stop the activity), you need to see your physician.