Vasovagal syncope

Have you, or any of your family members, been fainting too often without any apparent cause? Chances are, that Vasovagal syncope is the underlying reason for such episodes. Know all about this disorder, including its various causes, symotoms, diagnosis and treatment options.

Vasovagal syncope Definition

It refers to an episode of fainting or unconsciousness resulting from a hyperactive physical reflex that momentarily retards oxygen flow to the brain. It is this lack of proper oxygen supply to the brain that makes affected individuals lose consciousness.

The disorder is the most common cause of fainting. It is also known by various other names like:

  • Common faint
  • Reflex syncope
  • Neuromediated syncope
  • Neurocardiac syncope
  • Vasovagal response
  • Vasovagal attack
  • Neurocardiogenic syncope (NCS)

Vasovagal syncope ICD9 Code

The ICD9 Code for this condition is 780.2.

Vasovagal syncope Incidence

In the general population, the disease is said to have a 22% mean prevalence. The disease can arise at any age. However, it is increasingly been regarded as an important cause of unconsciousness in elderly people.

Vasovagal syncope Symptoms

The condition is typically characterized by sudden loss of consciousness or fainting on the part of sufferers. Prior to fainting, however, patients may suffer from certain other problems. These include:

  • Nausea
  • Lightheadedness
  • Cold, clammy and sweaty skin
  • Feeling of warmth
  • Paleness of skin
  • Tunnel vision, characterized by limiting of the field of vision to let patients see only the objects at the front

Loss of consciousness can be an early sign of a more severe condition, such as brain or heart disorders. Suffering individuals should get in touch with a good physician as early as possible, in case they have not experienced symptoms of fainting before.

Vasovagal syncope Causes

The problem arises when the body reacts aggressively to certain trigger factors. These include severe emotional trauma or the sight of blood. Such triggers lead to a sudden drop in blood pressure and heart rate. The section of the nervous system regulating the blood pressure and heart rate begins to malfunction in response to such trigger factors. The heart rate gets slowed down and the blood vessels present in the legs widen. This results in accumulation of blood in the legs and immediate lowering of blood pressure. The flow of blood to the brain gets reduced, ultimately leading to fainting in sufferers.

The common trigger factors for this condition include:

  • Severe emotional distress
  • The sight of blood
  • Standing for an extended duration
  • Exposure to heat
  • Drawing out of blood from the body
  • Straining, as in bowel movement
  • Fear of bodily harm

Vasovagal syncope Diagnosis

The diagnostic tests for this condition include the following exams:


This exam involves the use of ultrasound imaging to get a proper view of the heart and search problems, such as those involving the valves, which can result in fainting.


It includes recording the electrical signals produced by the heart of affected individuals. The test helps detect irregularities in cardiac rhythms and other heart problems that can lead to unconsciousness. Patients undergoing this exam may be asked to wear a portable monitor for some time, the span of which can range from a single day to an entire month.

Blood tests

These are useful for physicians to determine the presence of conditions like anemia that can result in, or worsen, the fainting spells in patients.

Exercise stress test

This exam studies cardiac rhythms during a period of workout. The test is generally carried out when patients walk under observation or jog on a treadmill.

Vasovagal syncope Differential Diagnosis

Physicians may recommend certain exams to rule out the presence of severer causes of sudden unconsciousness, such as heart disorders. The differential diagnosis of the disease should include ruling out other disorders that produce identical symptoms. These include:

  • Complex partial epilepsy
  • Panayiotopoulos syndrome
  • Hypoxia, with convulsion
  • Hysterical fainting
  • Acute blood loss
  • Hypoglycemia
  • Chronic fatigue syndrome
  • Neurodegenerative disorders
  • Primary autonomic failure, such as pure autonomic failure or multiple system atrophy

Physicians also keep in mind the effects of intake of drugs and alcohol while evaluating this condition.

If doctors detect no heart-related problems for the fainting episodes, they may suggest patients to go through a tilt-table test. The test involves:

  • Lying flat on the back over a table
  • Changing the position of the table to tilt the patient upward at several angles
  • Monitoring the blood pressure and cardiac rhythm to observe whether the postural change affects sufferers

A tilt-table test provokes NCS symptoms in a controlled setting while the blood pressure and cardiac rhythm are monitored. Following tests, medicines may be prescribed to minimize the symptoms experienced by sufferers.

Vasovagal syncope Treatment

The majority of sufferers of this disease do not require any treatment. Physicians may help affected individuals identify the trigger factors for their fainting episodes and discuss the possible ways to avoid or at least cope with them. If patients experience the problem as frequently as to have their daily activities impaired by it, physicians may suggest one or more remedial measures which include:


Certain drugs that can help avoid an occurrence of such episodes of unconsciousness. These involve:

Blood pressure medications

Beta blockers like Metoprolol (Lopressor) are used to cure high blood pressure problems. Such types of drugs are also used very frequently to prevent fainting episodes resulting from NCS as they obstruct some of the signals that can cause loss of consciousness.


The class of antidepressant drugs, known as SSRIs (Selective Serotonin Reuptake Inhibitors), has also been found to be useful in preventing cases of NCS. Sertraline (Zoloft), Fluoxetine (Prozac) and paroxetine (Paxil) are some of the SSRIs found to yield positive results in the management of NCS.

Blood vessel constrictors

In some patients, NCS can be prevented with the aid of drugs used to cure asthma or blood pressure.


Physicians may recommend the use of certain methods to reduce the accumulation of blood in the legs. Such techniques may involve:

  • Wearing elastic stockings
  • Foot exercises
  • Tensing the leg muscles while standing
  • Increasing the intake of dietary salt (for people not suffering from high blood pressure)
  • Having lots of fluids
  • Avoiding standing for long periods, particularly in crowded and hot places

The emotional causes of NCS may need intervention by a professional mental healthcare provider.


Inserting an electrical pacemaker can help regulate cardiac rhythm and help some individuals suffering from NCS.

Vasovagal syncope in Children

Children suffering from NCS typically complain of the following problems before having an actual episode of fainting:

  • Lightheadedness
  • Dizziness
  • Nausea
  • Changes in hearing or vision
  • A feeling of warmth

When kids faint and fall down, they tend to recover quickly. They are fully oriented almost always. However, they may experience nausea, weakness and tiredness for a few hours.

The physical injuries in children heal quickly. Unfortunately, that is not the case in adults. Elderly individuals who get injured due to a fall suffer for a much longer duration. Children who faint during sports activities should not be allowed to get back to strenuous activities until they have been completely evaluated and declared fit by a qualified healthcare provider. Affected kids should be put through the following tests:

  • Exercise testing
  • Echocardiography
  • Cardiac catheterization
  • Ambulatory cardiac rhythm monitoring

Even after treatment, kids who have suffered an episode of NCS should be encouraged to improve his or her daily fluid intake. Proper measures should be taken to reduce chronic emotional and physical stresses in NCS-affected children.

In a study conducted in young medical students, half of the girls and a quarter of the boys were found to suffer from at least one episode of fainting.

Vasovagal syncope and Pregnancy

Pregnant women are more susceptible to this condition. In pregnant women, the cardiovascular system goes through rapid changes. They experience lightheadedness as well as an array of other problems like:

  • Paleness of skin
  • Sweating
  • Sensation of hotness
  • Yawning
  • Nausea
  • Hyperventilation (deeper breathing)

These are nothing but the warning signs of NCS. Pregnant women who experience such problems should immediately lie down to prevent themselves from fainting. They should call their midwife or a doctor to share the problems and discuss possible remedial measures. Loss of consciousness during maternity can lead to a fall and carries a possible risk of miscarriage. Naturally, it is important for expecting mothers to seek treatment for this condition.

Vasovagal syncope Complications

This is generally a harmless condition. However, patients may injure themselves by falling down during an episode of fainting caused by this problem. Bodily injuries (such as bruises, broken bones or gashes) caused due to a fall or an accident suffered during unconsciousness can jeopardize health. In rare cases, severe injuries might also lead to the death of sufferers.

Vasovagal syncope Prognosis

Therapy involving medications can prevent future episodes of this nature. However, certain patients continue to suffer from such problems despite the use of medicines. Drugs are found to be ineffective in such cases.

Vasovagal syncope Prevention

It is difficult to prevent the condition as it is not known when an episode of fainting would occur. However, people who suffer from recurrent episodes of fainting associated to NCS tend to become familiar with the warning signs. A person experiencing the problems prior to fainting such as lightheadedness, nausea or tunnel vision should lie down and lift the legs to rest them in a higher place. This would keep the legs at a higher level than that of the brain. The blood flow to the brain would continue due to gravity. If there is no place to lie down, the person should sit down and place the head between the knees until he or she begins to feel better.


While Vasovagal syncope is not a serious problem, it involves a risk of certain complications and can be a warning sign of some other disorder in certain cases. Naturally, people experiencing more than one episodes of such type of sudden unconsciousness should get in touch with a medical professional and discuss possible course of remedy.


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