Related terms: (vasovagal episode/vasovagal response/vasovagal attack)
Vasovagal syncope is the common faint that may be experienced by normal persons with no evidence of heart disease.
The vagus nerve is the nerve of the muscle in the throat and the larynx, and is the nerve that slows the rate of the heartbeat and supplies the parasympathetic nerves to the lungs, the stomach, the esophagus, and other abdominal organs.
Stimulating the parasympathetic nerves generally produces vasodilation of the part supplied; in general, it slows the heart rate, decreases the blood pressure; contracts the pupils; causes copious secretion of the saliva; and increases gastrointestinal activity.
Stimulation of the vagus causes slowing of the heart rate and, if sufficient, can cause fainting or even cardiac arrest. Usually, when this happens, the heart’s ventricles start beating on their own despite continued vagal stimulation.
In the moment-to-moment regulation of heart rate at rest, the vagal influence is dominant and, particularly in athletes with low resting heart rates, this ‘vagal tone’ can be considerable.
Hypotension, or low blood pressure, is associated with increased nervous system activation and increased heart rate, but one type, hypovolemic hypotension, occurring after hemorrhage or certain drugs, induces a decrease in heart rate. Both effects result from abnormal excitation of the vagus nerve, and hence, the term used to describe the loss of consciousness that may result is vasovagal syncope.
- Postural Hypotension. Getting up very quickly can cause your blood pressure to fall so quickly that the upper part of your body will not get enough blood and hence oxygen and the circulation in the brain is disturbed. This causes the syncope.
- Diseases of the autonomic nervous system. Your autonomic nervous system is the part of your nervous system that controls involuntary vital functions, such as the beating of your heart, the degree to which your blood vessels are constricted, and breathing. Autonomic nervous system problems include acute or subacute dysautonomia, chronic post-ganglionic autonomic insufficiency, and chronic pre-ganglionic autonomic insufficiency. If you have one of these disorders, you are likely to have other serious symptoms, such as erectile dysfunction (inability to have or maintain an erection), loss of bladder and bowel control, loss of the normal reflexes of your pupils, or decreased sweating, tearing, and salivation.
- Conditions that interfere with the parts of the nervous system that regulate blood pressure and heart rate. These conditions include diabetes, alcoholism, malnutrition, and amyloidosis (in which waxy protein builds up in the tissues and organs). If you take certain high blood pressure medications, which act on your blood vessels, you may be more likely to suffer from fainting. If you are dehydrated, which may affect the amount of blood in your body and, thus, your blood pressure, you may be more likely to faint.
- Heart or blood vessel problems that interfere with blood flow to the brain. These may include heart block (a problem with the electrical impulses that control your heart muscle), problems with the sinus node (a specialized area of your heart that helps it beat), heart arrhythmia (irregular heart rhythm), a blood clot in your lungs, an abnormally narrowed aortic heart valve, or certain other problems with the structure of your heart.
- Conditions that may cause unusual patterns of stimulation to particular nerves. These include micturition syncope (fainting during or after urination), glossopharyngeal neuralgia (fainting due to inflammation and pain in a particular nerve to the mouth); cough syncope (fainting after intense coughing) and stretch syncope (fainting that occurs when stretching the neck and arms).
- Hyperventilation. If you become intensely anxious or panicked and breathe too quickly, you may faint from hyperventilation (taking in too much oxygen and getting rid of too much carbon dioxide too quickly).
- Give lots of electrolytes (ORS)
- Drink plenty of water
- Glucose solution is helpful
- Normal Saline may be indicated