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What is Brugada Syndrome?
Brugada syndrome is an uncommon but serious heart condition. It can cause fainting and episodes of an abnormally rapid heart rhythm, called arrhythmia. This happens because the electrical activity of the heart is disrupted – a problem that is usually inherited. Not everyone with Brugada syndrome will experience arrhythmia but, when it does happen, it can be fatal.
What is the underlying cause of Brugada Syndrome?
In Brugada syndrome the heart is structurally normal; however, there are problems with electrical activity. On the surface of each heart muscle cell are tiny pores, or ion channels. These open and close to let electrically charged sodium, calcium and potassium atoms (ions) flow into and out of the cells. This passage of ions generates the heart’s electrical activity. An electrical signal spreads from the top of the heart to the bottom, causing the heart to contract and pump blood.
Therefore, if the electrical properties of a cell are faulty, this can result in a disturbance of the heart rhythm (arrhythmia).
What are the signs and symptoms of Brugada Syndrome?
The warning signs of Brugada syndrome usually start in adulthood (at age 30-40) but may appear as early as infancy. They include:
- heart palpitations
- blackouts
- seizures
- cardiac arrest – when an abnormal heart rhythm causes the heart to stop beating.
Who is affected?
Brugada syndrome typically affects young and middle-aged males who are otherwise healthy, although women can also be affected. Men are more likely than women to show signs of it, possibly because of the sex hormone testosterone, which is thought to play a role.
Inherited Brugada Syndrome
People with hereditary Brugada syndrome will have inherited a mutated (altered) gene from one of their parents.
The SCN5A gene is most often involved but this is only found in a quarter of families. This gene provides instructions for making a sodium channel that transports positively charged sodium ions into heart muscle cells.
The mutation in this gene affects the proteins that make up the sodium channels, so they don’t work as well. There is a reduced flow of sodium ions into the heart cells, which alters the way the heart beats.
Only one copy of the altered gene in each cell is needed to cause the disorder. In most cases, an affected person has just one parent with the condition.
If you have a close family member who has either been diagnosed with the condition or who has died young from a suspected heart condition, it is very important that all remaining relatives are screened for Brugada syndrome.
Acquired Brugada Syndrome
Not all people with Brugada syndrome will have this gene mutation and there is not always a family history of it.
In those who appear to have acquired Brugada syndrome, the cause is unknown. However, certain drugs may play a role, including medication used to treat some forms of arrhythmia, angina, high blood pressure and depression.
Also, abnormally high blood levels of calcium or potassium, as well as abnormally low levels of potassium, have been associated with acquired Brugada syndrome.
How is it diagnosed?
If your doctor suspects that you may have Brugada syndrome he/she will advise you to have an Electrocardiograph (ECG) and may refer you to a Cardiologist who specializes in heart rhythm and genetic heart problems. If Brugada is suspected after your ECG, you’ll probably be referred for an Ajmaline test to confirm your diagnosis. Ajmaline is a drug which blocks sodium channels. As it blocks the faulty sodium channels, it unmasks ECG changes in patients with Brugada syndrome. In patients with normal cardiac cells, Ajmaline has little or no effect on the ECG.
Your doctor will only recommend you have an Ajmaline test if he/she feels that the benefits clearly outweigh the risks.
Other drugs can be used to test for Brugada syndrome but these take a lot longer to leave your system so patients need to be monitored for a longer period and any side effects may last longer. For these reasons, most hospitals worldwide use Ajmaline for this test.
What do I need to do before the test?
It is very important that you follow these fasting instructions, or your test may be cancelled. On the morning of your test, you may have an early breakfast, but you must not eat any food or milky drinks 6 hours before your procedure time. Milk counts as a food product as it takes longer to digest.
You may safely continue to drink clear fluids such as water, black tea, black coffee up until 2 hours before your procedure time. If you are on any regular medications or are diabetic, please contact the Arrhythmia team before your appointment day.
What happens before the Ajmaline test?
When you arrive at the ward you will be introduced to the nurse who will be looking after you. The nurse will explain the procedure to you and answer any worries or questions.
Before the procedure, the nurse will take your blood pressure and heart rate and then a use small needle to insert a plastic tube into a vein in your arm to allow the nurse to give you the Ajmaline. The nurse will take some blood and then record an ECG.
What happens during the Ajmaline test?
During the procedure you will be awake and able to talk. For the duration of the test, you will be connected to the ECG machine.
The nurse will administer the Ajmaline slowly over 5 minutes and will record an ECG every minute during the infusion and for a further 15 minutes after the infusion. By this time the Ajmaline should be out of your system and even if you have been shown to have the ECG changes associated with Brugada syndrome, your ECG would have returned to normal.
The nurse will offer you a drink and keep you in a monitored bed for approximately one hour.
After the Ajmaline Test
You should be able to go home approximately 1-2 hours after the test. You are allowed to drive yourself to and from the hospital.
In rare cases, if you have required a cardioversion, you will be monitored for a longer period; but if there are no problems you should still be allowed home the same day (we will advise against driving in this case).
Benefits
Making a diagnosis of Brugada syndrome is important as, if you have it, you are at risk of a fast heart rhythm developing.
A positive test may mean that you need other tests and treatment to prevent the problems associated with Brugada syndrome. Your doctor may suggest an electrophysiology study and ultimately you may be advised to have an Implantable Cardioverter Defibrillator (ICD) fitted. An ICD will not prevent arrhythmia but can treat it, should it happen. Also, because there is a hereditary factor, other family members may be tested with Ajmaline or offered genetic testing.
If the genetic test is negative, it may not rule out a genetic heart rhythm disorder and your genetics consultant/counsellor will be able to give more extensive advice.
If the test is negative, then this will provide reassurance that it is unlikely you have Brugada syndrome, and your doctor will consider your individual risk and advise you if further tests need to be performed.
Side effects and risks
The Ajmaline test is safe. However, as with any procedure, there are potential risks that may occur either during or after the procedure. Complications that occur with this test are very rare, can be treated and are rarely life threatening.
It is common (and harmless) to experience a metallic taste in the mouth while you are being given Ajmaline. You may also experience a very warm feeling, visual disturbances such as double vision and tingling of your lips. Such side effects usually resolve quickly once the infusion is completed.
Very rarely Ajmaline may cause your heart to go into a very fast rhythm. When this happens it often requires no treatment other than monitoring you while the drug wears off. Rarely, this heart rhythm can require urgent treatment with cardioversion (a controlled electrical shock to restore a normal rhythm).
If this is required, you will be given a sedative to make you sleepy and once you are asleep a machine called a defibrillator is used to send electrical energy to the heart muscle to restore it to normal rhythm and rate.
There have been no reports of deaths because of an Ajmaline test worldwide. You cannot have the test if you are pregnant, breastfeeding or have liver problems. Please inform us if this is the case.
More information can be found on the following websites:
SADS UK at www.sadsuk.org
Tel: 01277 811215 Email: info@sadsuk.org
Cardiac Risk in the Young (CRY) at www.c-r-y.org.uk
Tel: 01737 363222 Email: cry
British Heart Foundation at www.bhf.org.uk
Tel: 0300 330 3322 Email: supporterservices
Arrhythmia Alliance at www.
Tel: 01789 450 787 Email: info
Contact us
If you have any queries relating to this information, please contact the Cardiology service.
About this information
Service:
Cardiology
Reference:
C/019
Approval date:
7 August 2025
Review date:
1 August 2028
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Important note
This page provides general information only. It is developed by clinical staff and is reviewed regularly every 3 years for accuracy. For personal advice about your health, or if you have any concerns, please speak to your doctor.