ABC Medical Center > Diseases > Vasovagal Syncope

What is vasovagal syncope?

25 September 2025

Vasovagal syncope is a condition that causes a loss of consciousness by triggering a sudden decrease in both blood pressure and heart rate. This results in a lack of blood flow to the brain, which can cause fainting.

What is Syncope?

Vasovagal syncope, also known as neurocardiogenic fainting, is usually harmless and doesn’t require medical treatment. However, the loss of consciousness itself can pose risks, such as falls and injuries.

It’s always a good idea to seek medical attention if you experience an episode of this kind. A doctor can perform the necessary tests to identify or rule out any serious underlying brain or heart condition that may have caused the fainting.

Although the specific cause that triggers vasovagal syncope is unknown, a number of factors have been identified that can be triggers for an episode, such as:

  • Having blood drawn.
  • Fear of serious injury.
  • Straining excessively when having a bowel movement or coughing, among other things.
  • Standing for several hours without rest.
  • Being in high temperatures.
  • Witnessing an event or accident where there is a lot of blood.

It is important to differentiate vasovagal syncope from cardiac syncope. Although both conditions cause a temporary loss of consciousness due to a decrease in cerebral blood flow, the cause is different.

As mentioned, vasovagal syncope is a temporary loss of consciousness caused by a reflex response of the autonomic nervous system. It’s usually triggered by stress, heat, or emotions, and is often a benign condition. Cardiac syncope, on the other hand, is the result of structural or electrical problems of the heart, such as arrhythmias or valvular stenosis, and can be life-threatening in some cases.

Signs and symptoms Vasovagal Syncope

The symptoms are:

  • Dilated pupils.
  • Slow heart rate.
  • Weak pulse.
  • Decreased blood pressure.
  • Paleness.
  • Confusion and lightheadedness.
  • Reduction of the visual field.
  • Nausea.
  • Intense heat.
  • Excessive cold sweating.
  • Blurred vision.

Diagnosis Vasovagal Syncope

The diagnosis of vasovagal syncope is based primarily on a detailed clinical history and the description of the syncopal event.

It is essential that the doctor asks the patient about the circumstances in which the fainting occurred, as well as any previous symptoms that might include blurred vision, nausea, sweating, or a feeling of heat, followed by a quick recovery after the episode.

Additionally, they will ask about common triggers such as the presence of pain, emotional stress, standing for long periods, or being in hot places.

The physical exam includes measuring blood pressure both lying down and standing up, which helps rule out other causes.

An electrocardiogram is a basic tool to identify heart rhythm abnormalities that could be confused with vasovagal syncope.

Treatment Vasovagal Syncope

Treatment for vasovagal syncope focuses mainly on patient education and modifying triggering factors. It is recommended to avoid situations that favor the onset of episodes and to learn physical counter-pressure maneuvers that can help maintain venous return and prevent fainting.

If a person has recurrent cases of vasovagal syncope or a significant impact on their quality of life, the use of pharmacological treatment may be considered.

In very specific situations, such as syncope with documented asystole, the implantation of a pacemaker may be evaluated.

At the Arrhythmia Clinic of Centro Médico Saludora, we can provide you with specialized care. Contact us!

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    Ricardo Ostos

    Ricardo Ostos

    Content Creator

    Ricardo can convey complex medical information in an accessible and friendly way so that all of our patients can understand and benefit from it. In addition, he has an empathetic approach, offering information and practical advice that really makes a difference in people's lives. #lifebringsustogether.

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    The dissemination of the content of this material is for informational purposes only and does not replace, under any circumstance or condition, a consultation with a specialist doctor, for which the Saludora Medical Center is not responsible for the different use that may be given to it. If you require more information related to the subject, we suggest you contact the specialist doctor you trust directly.