This information is useful for children and adults
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Why Yale Medicine?
  • Our doctors use state-of-the-art technology to treat and diagnose syncope.
  • Our doctors are leading researchers in their fields.
  • Our doctors participate in clinical research that allows them to offer medications and treatments to patients not available to the public.

Some people faint from the sight of blood. Others may faint because they’re dehydrated. In other cases, serious heart conditions may cause an abnormal rhythm, preventing the heart from sending sufficient blood and oxygen to the brain and leading to a loss of consciousness. 

While some fainting is not a cause for concern, it’s critical to identify the cause and to treat any serious underlying conditions. In some cases, fainting can be caused by problems with the heart’s valves or arteries.

 At Yale Medicine, our doctors use state-of-the-art technology to diagnose and treat this condition.

There are two types of syncope: vasovagal syncope and cardiac syncope.  

Vasovagal syncope accounts for more than half of fainting incidents. When a person experiences extreme pain or fear, sees something that disgusts them (such as blood) or stands for a long period, it can cause an abnormal reflex in the part of the nervous system that regulates heart rate and blood pressure. This causes the heart rate to slow and decreases the amount of blood flowing to the brain, which causes a person to faint. Sometimes, if a person has prolonged vasovagal syncope, it can trigger a seizure.

Cardiac syncope occurs when the heart is not pumping enough blood to the brain. This can occur because of an abnormal heart rhythm that is either too slow or too fast. This can also occur if there is a problem with heart structure or function that causes the pumping function to become ineffective.

Clinical Trials

New treatments for many conditions are tested in clinical trials, which ultimately bring lifesaving new drugs and devices to the patients who need them most. By participating in a clinical trial, you may get access to the most advanced treatments for your condition, and help determine their benefits for future patients.