Brugada syndrome is an inherited disorder of the heart’s electrical system that can result in an abnormal heart beat (arrhythmia). When your heart is functioning normally, each heartbeat is triggered by electrical signals that are generated by certain cells in the right upper chamber (right atrium). Brugada syndrome occurs when there is a defect in the tiny pores of these cells (called channels), restricting their ability to move sodium normally.
This defect can lead to episodes of abnormal electrical activity, which can cause a dangerous kind of arrhythmia in which the lower chambers (ventricles) beat so fast (ventricular tachycardia or ventricular fibrillation) that the heart cannot pump the blood it needs for the brain to work normally. Arrhythmia episodes can occur suddenly, leading to fainting, or sometimes to cardiac arrest and sudden death.
Although the average age of a patient with sudden cardiac death is 35 to 40 years old, patients with inherited arrhythmias may range from 6 months to 75 years old.
Background
Brugada syndrome is a newly discovered, newly defined disease. The first patient with this condition (a 3-year-old boy from Poland) was seen in 1986, and the first description of it in English literature did not appear until 1992. However, it was soon discovered that the Centers for Disease Control had described a high incidence of sudden cardiac death in immigrants from Asia in the 1980s. In addition, a similar problem had been described in Thailand, Japan and the Philippines for many years.
Prevalence
The condition occurs much more frequently in people of Asian ancestry, particularly in Southeast Asian populations. Although it affects both men and women, the condition appears to be more common in men. The exact prevalence of Brugada syndrome is unknown, although it is estimated to affect five in 10,000 people worldwide, according to the National Institutes of Health.
Causes
Although Brugada syndrome typically has a genetic cause, sometimes it is acquired (meaning it is not inherited but has an environmental cause). Usually, the acquired form is prompted by certain medications. Still researchers believe that even when a drug appears to have caused it, these patients are predisposed to developing the condition due to genetic reasons.
Signs and Symptoms
Some people do not experience signs or symptoms during an arrhythmia episode, while others may experience any of the following:
- pounding or fluttering in the chest
- shortness of breath
- seizure
- fainting spells (syncope)
- arrhythmias that occur during sleep (possibly leading to sudden cardiac death)
Diagnosis
When Brugada syndrome is suspected, a patient is typically referred to a doctor that specializes in heart disease (cardiologist) or a cardiologist that specializes in heart rhythms (an electrophysiologist). A careful evaluation including a family health history and physical examination are performed.
As with other inherited arrhythmias, Brugada syndrome can be difficult to diagnose. Although it is usually detected on an electrocardiogram, sometimes the ECG findings are very subtle, which is why it is so important to see a specialist. Sometimes, certain medications are given to unmask the subtle changes that identify a person at risk for an arrhythmia.
There are a number of conditions which may cause a Brugada pattern on an ECG, and because of the implications of the diagnosis, these conditions must be ruled out. If someone faints without an unidentifiable cause (particularly a younger person in which all other tests are normal) that person should be evaluated by a cardiac electrophysiologist using testing that is only available within this specialty.
If someone has a history of fainting and is found to have Brugada syndrome, the likelihood that this person will experience recurring episodes of fainting or sudden cardiac death is up to 40 percent during the next 2-3 years.
Management and Treatment
To manage Brugada syndrome, doctors frequently recommend either an electrophysiology (EP) study to monitor the condition or a special device that is implanted near the shoulder called an implantable cardioverter defibrillator (ICD) that can prevent an arrhythmia attack:
- EP study – This is a 1-2 hour procedure that allows your doctor to assess the electrical system in the heart using special types of catheters, which are long floppy wires that are placed in the heart to sense the heart’s activity and pace the heart when needed. The EP study is used to identify the type of abnormal rhythm and determine the effect of certain medications. No treatments are performed in the EP lab, but the study may provide important information, such as your risk for passing out or possibly dying from an arrhythmia. If your doctor schedules an EP test, it is important to discuss what medications you are taking. Some medications must be stopped anywhere from 24 hours to a week prior to the EP study.
- ICD – This implantable device is tiny - about the size of a small pager - and getting smaller with each innovation. An ICD can detect and prevent the kind of arrhythmias responsible for causing patients to faint or die. If the ICD detects this type of arrhythmia, it sends energy to the heart to “shock” it back to a normal rhythm. When provided with an ICD, the rate of death in patients with Brugada syndrome has been 0 percent with up to 10 years follow-up.
If you have Brugada syndrome, it is important that your siblings and children be screened for the condition.
