Brugada Syndrome: A Heart Rhythm Disorder That Can Lead to Sudden Cardiac Arrest

Unexplained fainting, heart palpitations, abnormal breathing during sleep, or a family history of sudden death at a young age may be signs that require further medical evaluation. One condition that doctors may consider is Brugada syndrome.

Brugada syndrome is a rare disorder affecting the heart’s electrical system. In some people, it can cause serious abnormal heart rhythms in the lower chambers of the heart and may lead to sudden cardiac arrest.

Some people with Brugada syndrome have no symptoms and may not know they have the condition until an abnormal electrocardiogram (ECG) is detected or a cardiac event occurs. Therefore, people with suggestive symptoms or a relevant family history should receive appropriate medical evaluation.

What Is Brugada Syndrome?

Brugada syndrome is a condition in which the heart’s electrical system functions abnormally. This can increase the risk of rapid and irregular heart rhythms, particularly ventricular arrhythmias originating in the lower chambers of the heart.

One of the most dangerous arrhythmias associated with the condition is ventricular fibrillation (VF). During ventricular fibrillation, the lower chambers of the heart quiver rapidly instead of contracting effectively. As a result, the heart cannot adequately pump blood to the brain and other vital organs.

Without immediate treatment, ventricular fibrillation can lead to sudden cardiac arrest and death.

Brugada syndrome is often associated with genetic abnormalities affecting ion channels in heart muscle cells. These channels play an important role in generating and conducting the heart’s electrical signals. However, a disease-causing genetic variant cannot be identified in every person diagnosed with Brugada syndrome.

Why Is Brugada Syndrome Important?

Brugada syndrome is important because some people may have no obvious structural heart disease and can live normally while still being at risk of developing a serious cardiac arrhythmia.

Arrhythmias associated with Brugada syndrome can occur while a person is resting or sleeping. Fever and certain medications may also make the characteristic ECG abnormalities more apparent or trigger arrhythmias in susceptible individuals.

Brugada syndrome has also been associated with Sudden Unexplained Nocturnal Death Syndrome (SUNDS), a condition involving sudden unexplained death during sleep that has been reported particularly among populations in Southeast Asia.

Causes and Factors Associated With Brugada Syndrome

Brugada syndrome is associated with abnormalities in the electrical activity of the heart. Important factors include:

• Genetics: Some patients have genetic changes affecting ion channels in heart cells.
• SCN5A gene: SCN5A is one of the genes most commonly associated with Brugada syndrome. It is involved in the function of cardiac sodium channels, which play an important role in the heart’s electrical activity.
• Family history: Brugada syndrome can run in families. However, having a related genetic variant does not mean that every person will experience the same symptoms or level of risk.
• Fever: A high body temperature can make the Brugada ECG pattern more apparent and may trigger dangerous arrhythmias in some patients.
• Certain medications: Some medicines can affect the electrical activity of the heart and may increase the risk of arrhythmias in people with Brugada syndrome.
• Electrolyte abnormalities: Abnormal levels of electrolytes, such as potassium, may affect the heart’s electrical activity.

Symptoms and Warning Signs

Many people with Brugada syndrome have no symptoms. When an abnormal heart rhythm occurs, possible symptoms include:

• Heart palpitations or an awareness of an abnormal heartbeat
• Dizziness or lightheadedness
• Unexplained fainting or loss of consciousness
• Difficulty breathing or abnormal breathing during sleep
• Seizures, which may sometimes occur when an arrhythmia reduces blood flow to the brain
• Sudden cardiac arrest

These symptoms do not necessarily mean that a person has Brugada syndrome because they can also occur with other medical conditions. Medical evaluation is therefore necessary to determine the underlying cause.

When Should You Seek Emergency Medical Care?

Seek immediate medical attention if any of the following occurs:

• Unexplained loss of consciousness or fainting, particularly while resting or sleeping
• Severe palpitations accompanied by dizziness or loss of consciousness
• Severe abnormal breathing or difficulty breathing
• Unexplained seizures
• Sudden cardiac arrest

Who May Be at Risk of Brugada Syndrome?

Medical evaluation should be considered for people who:

• Have a family member diagnosed with Brugada syndrome
• Have a family history of unexplained sudden death, particularly at a young age
• Have experienced unexplained fainting
• Have previously experienced a serious cardiac arrhythmia
• Have survived sudden cardiac arrest
• Have an ECG showing a pattern suspicious for Brugada syndrome

When a family member is diagnosed with Brugada syndrome, doctors may recommend evaluation of close relatives, such as parents, siblings, or children, depending on the individual situation.

How Is Brugada Syndrome Diagnosed?

An important diagnostic test is an electrocardiogram (ECG or EKG), which records the electrical activity of the heart and may identify patterns associated with Brugada syndrome.

However, the characteristic ECG pattern may not be present all the time. Therefore, a single ECG may not detect the condition in every patient.

Additional tests may include:

• Repeated ECGs or ECGs using modified electrode positions
• A sodium channel blocker challenge performed under close medical supervision
• Heart rhythm monitoring, such as a Holter monitor, in selected cases
• Echocardiography to evaluate the structure and function of the heart
• Electrophysiological studies in selected patients
• Genetic testing when clinically appropriate

Finding a Brugada ECG pattern alone does not necessarily mean that every person has the same level of risk. Doctors must consider symptoms, family history, ECG findings, and other clinical factors when assessing each patient.

Treatment of Brugada Syndrome

Treatment depends on the individual patient’s risk. People who have no symptoms and are considered at low risk may not require medication or an implanted device, but they should receive advice about potential triggers and appropriate medical follow-up.

For patients at higher risk, treatment may include:

• Implantable Cardioverter-Defibrillator (ICD): An implantable cardioverter-defibrillator (ICD) continuously monitors the heart rhythm and can deliver an electrical shock when a life-threatening arrhythmia is detected. An ICD may be considered for people who have survived cardiac arrest or who are considered at high risk of developing a dangerous ventricular arrhythmia.
• Medication: Some patients may receive medications to help control or prevent arrhythmias. For example, quinidine may be considered in certain clinical situations. The choice of medication must be determined and monitored by a doctor.
• Radiofrequency Catheter Ablation: In selected patients, particularly those experiencing recurrent ventricular arrhythmias or repeated appropriate ICD shocks, doctors may consider radiofrequency catheter ablation to treat areas of heart tissue associated with abnormal electrical activity.

Treatment decisions should be individualized according to symptoms, previous arrhythmias, ECG findings, and other risk factors.

Self-Care for People With Brugada Syndrome

People diagnosed with Brugada syndrome should follow their doctor’s recommendations carefully. Important considerations include:

• Fever should be managed promptly according to medical advice because fever can trigger abnormal heart rhythms in susceptible individuals.
• Inform doctors and pharmacists about Brugada syndrome before starting a new medication.
• Do not start, stop, or change medications without consulting a healthcare professional.
• Inform the medical team before surgery, anesthesia, or sedation.
• Avoid medications and substances identified by healthcare professionals as potential triggers for arrhythmias.
• Attend scheduled medical follow-up appointments.
• Discuss exercise and competitive sports with a doctor to determine what is appropriate based on individual risk.

People with an ICD should also follow instructions regarding device care and attend regular device monitoring appointments.

Who Should Consult a Doctor?

Consider consulting a doctor, particularly a cardiologist, if you:

• Have experienced unexplained fainting
• Experience palpitations accompanied by dizziness or loss of consciousness
• Have survived unexplained cardiac arrest
• Have a family member with Brugada syndrome
• Have a family history of sudden unexplained death at a young age
• Have an ECG showing abnormalities suspicious for a Brugada pattern
• Have been diagnosed with Brugada syndrome and are planning to start a new medication or undergo surgery

Summary

Brugada syndrome is a disorder of the heart’s electrical system that can increase the risk of serious ventricular arrhythmias and sudden cardiac arrest. Some people have no symptoms, making a history of unexplained fainting, family history, and ECG findings important parts of the medical evaluation.

People diagnosed with Brugada syndrome should receive appropriate medical follow-up, avoid known triggers and medications that may increase their risk, and pay particular attention to the management of fever.

If unexplained loss of consciousness, severe palpitations with dizziness, or signs of sudden cardiac arrest occur, immediate medical attention is necessary.

Prepared by: Poonyanuch Angkanawin, Pharm.D.

References

1. MedlinePlus Genetics. Brugada Syndrome
2. Mayo Clinic. Brugada Syndrome: Symptoms and Causes
3. Mayo Clinic. Brugada Syndrome: Diagnosis and Treatment