What You Should Know About Brugada Syndrome
Brugada syndrome is an uncommon, inherited abnormality of the heart's electrical system. It can have two notable consequences even in apparently healthy young people.
First, it can lead to the lower chambers of the heart quivering, rather than pumping blood as they should, causing an abnormal heart rhythm (ventricular tachycardia or ventricular fibrillation). Ventricular fibrillation, and sometimes ventricular tachycardia, can cause sudden cardiac arrest or death. These arrhythmias may also lead to syncope (passing out).
In contrast to most other conditions that cause sudden death in young people, the arrhythmias produced by Brugada syndrome usually occur during sleep, not during exercise.
Brugada Syndrome Symptoms
The most devastating problem caused by Brugada syndrome is sudden death during sleep.
However, people with Brugada syndrome may experience episodes of any of the following prior to the fatal event:
Fainting
Syncope (loss of consciousness)
Nighttime seizures
Gasping and labored breathing (agonal respiration) while asleep
If these non-fatal episodes are brought to a doctor’s attention, a diagnosis can be made and treatment instituted to prevent subsequent sudden death.
Brugada syndrome has been identified as the cause of mysterious sudden unexplained nocturnal sudden death syndrome, or SUNDS.
SUNDS was first described as a condition affecting young males in Southeast Asia. It has since been recognized that these young Asian men have Brugada syndrome, which is far more prevalent in that part of the world than in most other places.
Causes
Brugada syndrome appears to be due to one or more genetic abnormalities that affect the cardiac cells, and in particular, the genes that control a sodium channel.
It is inherited as an autosomal dominant trait, meaning that only one parent needs to pass the abnormal gene down for a child to get it. But not everyone who has the abnormal gene(s) is affected in the same way. Furthermore, a specific gene hasn't been found for around 70% of affected families.
The electrical signal that controls the heart rhythm is generated by channels in the cardiac cell membranes, which allow charged particles (called ions) to flow back and forth across the membrane. The flow of ions through these channels produces the heart's electrical signal.
One of the most important channels is the sodium channel, which allows sodium to enter cardiac cells. In Brugada syndrome, the sodium channel is partially blocked, so that the electrical signal generated by the heart is altered. This alteration leads to an electrical instability that, under some circumstances, can produce ventricular fibrillation.
The only cardiac abnormality found with this syndrome is an electrical one. The hearts of people with Brugada syndrome are structurally normal.
In addition, people with Brugada syndrome may have a form of dysautonomia—an imbalance between sympathetic and parasympathetic tone. It is suspected that the normal increase in parasympathetic tone that occurs during sleep may be exaggerated in people with Brugada syndrome, and that this strong parasympathetic tone may trigger the abnormal channels to become unstable, and produce sudden death.
Other factors that can trigger a fatal arrhythmia in people with Brugada syndrome include fever, cocaine use, excessive alcohol intake and the use of various medications, especially certain antidepressant drugs.
Who Gets Brugada Syndrome?
Most people diagnosed with Brugada syndrome based on symptoms are young to middle-aged adults.
Brugada syndrome is seen eight to 10 times more often in men than in women.
It is known to occur more often in people of southeast Asian descent due to genetics; as many as 1 in 1,000 people in this population are affected.
Because Brugada syndrome has only been recognized since the early 1990s in western medicine, and because experts changed how Brugada syndrome was defined in 2013, it's pretty difficult to know exactly how many people have it.
Some estimate that 1 in 5,000 people may have Brugada syndrome.
Diagnosis
The electrical abnormality caused by Brugada syndrome can produce a characteristic pattern on the electrocardiogram (ECG), a pattern that is actually called the Brugada pattern. This consists of a specific "coved" triangle shape accompanied by elevations of the ST segments in leads V1 and V2.
Not everyone with Brugada syndrome has a “typical” Brugada pattern on their ECG initially, though they may show another "saddle-back" pattern. When these people are given a medication like procainamide that blocks the sodium channels, they show a "typical" Brugada pattern. However, this drug can be very dangerous for these patients, so this type of diagnostic testing must be done by an expert.
If Brugada syndrome is suspected (because, for instance, syncope has occurred or a family member has died suddenly in their sleep), a specialist familiar with it may be needed to evaluate whether an “atypical” Brugada pattern may be present or if more diagnostic testing is needed.
If a person’s ECG displays the Brugada pattern, and if he or she has also had episodes of unexplained severe dizziness or syncope, has survived a cardiac arrest, or has a family history of sudden death below the age of 45, the risk of sudden death is high. However, if the Brugada pattern is present and none of these other risk factors has occurred, the risk of sudden death appears much lower.
People with Brugada syndrome who have a high risk of sudden death should be treated aggressively. But in those who have the Brudada pattern on their ECG but no other risk factors, deciding how aggressive to be is not nearly as clear-cut.
Electrophysiologic Testing
Electrophysiologic testing (EP) has been used to help with this more difficult treatment decision, by clarifying an individual's risk of sudden death. The ability of electrophysiologic testing to accurately assess that risk is far less than perfect.
In most cases of asymptomatic Brugada, EP testing is not needed. Still, major professional societies say it may be considered in people who have the typical Brugada pattern on their ECGs without additional risk factors.
Genetic Testing
Genetic testing can help confirm the diagnosis of Brugada syndrome, but is usually not helpful in estimating a patient's risk of sudden death.
Furthermore, genetic testing in Brugada syndrome is quite complex and often does not yield definitive answers. It can, however, be useful in identifying affected family members.
Testing of Family Members
Because Brugada syndrome is a genetic disorder, current recommendations call for screening all first-degree relatives of anyone who is diagnosed with this condition.
Screening should consist of examining an ECG and taking a careful medical history looking for episodes of syncope or other symptoms.
Treatment
The most well-proven method of preventing sudden death in Brugada syndrome is inserting an implantable defibrillator (ICD).
In general, antiarrhythmic drugs should be avoided. Because of the way these drugs work on the channels in the cardiac cell membranes, they not only fail to reduce the risk of ventricular fibrillation in Brugada syndrome, but they may actually increase that risk.
A medication called quinidine and ablation therapy have both shown some success in treating Brugada syndrome. However, quinidine has many unpleasant side effects, and neither treatment has enough evidence behind it to be recommended yet.
Amiodarone may also be used in patients who have recurrent arrhythmias resulting in ICD shocks or in patients who refused an ICD.
There are certain medications that should be avoided in patients with Brugada syndrome, so always tell your provider about any medications you are currently taking; fevers also need to be treated quickly in people with this condition.
Whether someone with Brugada syndrome should receive an implantable defibrillator depends on whether their risk of sudden death is finally judged to be high or low.
If the risk is high (based on symptoms or electrophysiologic testing), a defibrillator should be recommended. But implantable defibrillators are expensive and carry their own complications. So if the risk of sudden death is judged to be low, these devices are not currently recommended.
People who are diagnosed with Brugada syndrome can almost always avoid a fatal outcome with appropriate treatment and can expect to live very normal lives.
Exercise Recommendations
Any time a young person is diagnosed with a cardiac condition that can produce sudden death, the question of whether it is safe to exercise must be asked. This is because most arrhythmias that produce sudden death in young people are more likely to occur during exertion.
In Brugada syndrome, in contrast, fatal arrhythmias are much more likely to occur during sleep than during exercise. Still, it is assumed (with little or no objective evidence) that strenuous exertion may pose a higher-than-normal risk in people with this condition.
For this reason Brugada syndrome is included in the formal guidelines generated by expert panels that have addressed exercise recommendations in young athletes with cardiac conditions.
Initially, guidelines regarding exercise with Brugada syndrome were quite restrictive. The 2005 36th Bethesda Conference on Eligibility Recommendations for Competitive Athletes with Cardiovascular Abnormalities recommended that people with Brugada syndrome avoid high-intensity exercise altogether.
However, this absolute restriction has subsequently been recognized as being too severe. In view of the fact that the arrhythmias seen with Brugada syndrome typically do not occur during exercise, these recommendations were liberalized in 2015 under new guidelines from the American Heart Association and the American College of Cardiology.
According to the 2015 recommendations, if young athletes with Brugada syndrome have had no symptoms associated with exercise, it is reasonable for them to participate in competitive sports if:
They, their physicians, and parents or guardians understand the potential risks involved and have agreed to take necessary precautions.
They avoid becoming overheated from fever or heat exhaustion.
They avoid medications that can make Brugada syndrome worse.
They stay adequately hydrated.
An automatic external defibrillator (AED) is a normal part of their personal sports equipment.
Team officials are able and willing to use the AED and perform CPR if necessary.
A Word From Verywell
Brugada syndrome is an uncommon genetic condition that causes sudden death, usually during sleep, in otherwise healthy young people. The trick is to diagnose this condition before an irreversible event occurs.
This requires doctors to be alert to the subtle ECG findings that are seen with Brugada syndrome—especially in anyone who has had syncope or unexplained episodes of lightheadedness.
