Brugada syndrome (patient information)

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Brugada syndrome
Overview
What are the symptoms?
What are the causes?
Who is at highest risk?
Diagnosis
When to seek urgent medical care?
Treatment options
Where to find medical care for Brugada syndrome?
Prevention
What to expect (Outlook/Prognosis)?
Possible complications
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Brugada syndrome is a condition that causes a disruption of the heart's normal rhythm. Specifically, this disorder can lead to uncoordinated electrical activity in the heart's lower chambers (ventricles), an abnormality called ventricular arrhythmia. If untreated, the irregular heartbeats can cause fainting (syncope), seizures, difficulty breathing, or sudden death. These complications typically occur when an affected person is resting or asleep.

What are the symptoms of Brugada syndrome?

Brugada syndrome usually becomes apparent in adulthood, although signs and symptoms, including sudden death, can occur any time from early infancy to old age. The mean age of sudden death is approximately 40 years. This condition may explain some cases of sudden infant death syndrome (SIDS), which is a major cause of death in babies younger than one year. It is characterized by sudden and unexplained death, usually during sleep.

Sudden unexplained nocturnal death syndrome (SUNDS) is a condition characterized by unexpected cardiac arrest in young adults, usually at night during sleep. This condition was originally described in Southeast Asian populations, where it is a major cause of death. Researchers have determined that SUNDS and Brugada syndrome are the same disorder.

What causes Brugada syndrome?

Mutations in the SCN5A gene cause Brugada syndrome.

Mutations in the SCN5A gene have been identified in fewer than one-third of people with Brugada syndrome. This gene provides instructions for making a sodium channel, which normally transports positively charged sodium atoms (ions) into heart muscle cells. This type of ion channel plays a critical role in maintaining the heart's normal rhythm. Mutations in the SCN5A gene alter the structure or function of the channel, which reduces the flow of sodium ions into cells. A disruption in ion transport alters the way the heart beats, leading to the abnormal heart rhythm characteristic of Brugada syndrome.

In affected people without an identified SCN5A mutation, the cause of Brugada syndrome is often unknown. In some cases, certain drugs may cause a nongenetic (acquired) form of the disorder. Drugs that can induce an altered heart rhythm include medications used to treat some forms of arrhythmia, a condition called angina (which causes chest pain), high blood pressure, depression, and other mental illnesses. Abnormally high blood levels of calcium (hypercalcemia) or potassium (hyperkalemia), as well as unusually low potassium levels (hypokalemia), also have been associated with acquired Brugada syndrome. In addition to causing a nongenetic form of this disorder, these factors may trigger symptoms in people with an underlying SCN5A mutation.

Who is at highest risk?

This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person has one parent with the condition. Other cases may result from new mutations in the gene. These cases occur in people with no history of the disorder in their family.

Diagnosis

The diagnosis of Brugada syndrome relies on the findings of the electrocardiogram (ECG) and electophysiologic studies.

When to seek urgent medical care?

Patients with Brugada syndrome should immediately be transported to the hospital if they suffer from cardiac arrest. Patients should seek medical care when there are symptoms such as syncope, seizures, or shortness of breath.

Treatment options

Implantation of a cardiac defibrillator is the only proven method of treatment in Brugada syndrome. Asymptomatic patients who cannot be induced by electrophysiologic studies and those with no family history of Brugada syndrome can be followed-up closely.

Medications to avoid

Patients diagnosed with brugada syndrome should avoid using the following medications:

• Propafenone
  If you have been diagnosed with brugada syndrome, consult your physician before starting or stopping any of these medications.

What to expect (Outlook/Prognosis)?

Brugada syndrome usually becomes apparent in adulthood, although it may present in infants and children as sudden cardiac death. The mean age of sudden death in patients with Brugada syndrome is 40 years old. The Brugada patient may develop atrial arrhythmia.

Possible complications

Sudden death can occur among patients with Brugada's syndrome.