Brugada syndrome is a genetic disorder that can cause a dangerous irregular heartbeat. When this happens, the lower chambers of your heart (ventricles) beat fast and irregularly. This prevents blood from circulating correctly in your body. It can be dangerous and may lead to fainting or even death, especially during sleep or rest. The disease has been called sudden, unexplained nocturnal death syndrome because people with it can die in their sleep.

Brugada syndrome is rare. It affects about 5 of every 10,000 people worldwide. Symptoms often start during adulthood. But the disorder can develop at any age, including infancy. The average age when the syndrome is first diagnosed is around 40 years old.

The genetic form of Brugada syndrome is most often caused by a defect in certain genes that handle sodium. But other genes can be involved too. It can be inherited from just one parent. But some people develop a new defect of the gene rather than getting it from a parent. The defects cause sodium channels in the heart muscle cells to not work properly. This may lead to abnormal heart rhythms.

It's possible to have Brugada syndrome that stays inactive (dormant) and doesn't cause any problems. But some medicines can unmask the syndrome. These include antidepressants and antipsychotics, drugs, conditions that cause fever, and electrolyte problems.

Some people may seem to have Brugada syndrome based on what's seen on an electrocardiogram (ECG). But they don't actually have the syndrome itself. This is called a Brugada ECG pattern. It may not pose a risk if the condition is short-term (temporary) and it doesn't cause symptoms or dangerous heart rhythms.

People of Asian descent, particularly of Japanese and Southeast Asian heritage, are at greatest risk for the disorder. It occurs 8 to 10 times more often in men than in women. Researchers think the male hormone testosterone may contribute to the difference between genders.

Symptoms that may occur with Brugada syndrome include:

• Palpitations.
• Fainting.
• Sudden death or cardiac arrest.

Your doctor may think you have Brugada syndrome if you have any of the above symptoms not explained by another more common condition. They may also suspect it if you have a family history of the disease or an unexplained sudden death in the family. An electrocardiogram (ECG) can help diagnose the disease. People with typical ECG features are often diagnosed with this condition if they've had:

• Fainting.
• Sudden cardiac death.
• Fast heart rate starting from the heart's bottom chambers (ventricular tachyarrhythmia).
• Family history of sudden cardiac death or Brugada syndrome.

Genetic testing can also be done to help diagnose the condition.

You may have a test called a drug challenge if the diagnosis is unclear or if you have the Brugada ECG pattern but have no symptoms. This is done in a hospital with professional supervision. You are given a medicine that blocks sodium channels. Then several ECGs are done to look for changes.

First-degree relatives of someone with Brugada syndrome should be screened. This may include at least a health history, physical exam, and an ECG. Genetic screening may also be done.

Currently, there is no cure for Brugada syndrome. But there are ways to protect people from the dangerous outcomes of the disease. An implanted cardioverter defibrillator (ICD) can help prevent sudden death linked to Brugada syndrome. When it detects the start of an arrhythmia (irregular heartbeat), it will either try to stop it with pacing or deliver a shock to reset it back into its regular rhythm.

Medicines may also help prevent arrhythmias. Another possible, but rare, treatment choice may be a cardiac ablation. In this procedure, a small area of heart tissue found to cause the dangerous arrhythmia is destroyed. Discuss all choices with a qualified doctor.

It's also important to stay away from certain medicines that can make Brugada syndrome worse.

The most serious complication of Brugada syndrome is sudden death. This typically occurs while the person is sleeping.

Many cases of Brugada syndrome are related to a genetic defect. It's not possible for you to prevent inheriting this condition. But identifying the condition is key to preventing its possible complications. You may first want to talk with a genetic counselor if you have Brugada syndrome and plan to have children.

If you have any symptoms of ventricular arrhythmia, call 911 and get emergency medical help right away. See a doctor for testing if you think you may be at risk for Brugada syndrome because of your family history or other reasons.

• Brugada syndrome is a genetic disorder that causes an irregular heartbeat.
• Genetic testing can look for a mutation, such as with the SCN5A gene, that may help determine your risk.
• An implanted cardioverter defibrillator (ICD) may be considered to prevent sudden death linked to the syndrome if Brugada syndrome is diagnosed.
• Get emergency medical help right away if you have any symptoms of ventricular arrhythmia.

Tips to help you get the most from a visit to your doctor:

• Know the reason for your visit and what you want to happen.
• Before your visit, write down questions you want answered.
• Bring someone with you to help you ask questions and remember what your doctor tells you.
• At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your doctor gives you.
• Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
• Ask if your condition can be treated in other ways.
• Know why a test or procedure is recommended and what the results could mean.
• Know what to expect if you do not take the medicine or have the test or procedure.
• If you have a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your doctor if you have questions, especially after office hours or on weekends.