Brugada Syndrome

Your heart’s electrical system normally follows predictable patterns as signals travel through heart muscle, creating the coordinated contractions that pump blood. Brugada syndrome is an inherited condition where abnormal electrical properties in your heart create a specific pattern and increase risk for dangerous, potentially fatal heart rhythms. What makes this condition particularly concerning is that your heart muscle and structure are completely normal—the problem is purely electrical. Many people with Brugada syndrome never have symptoms, living their entire lives unaware they carry this genetic abnormality. Others experience sudden cardiac arrest, sometimes during sleep or rest, as their first and potentially fatal manifestation.

Overview

Brugada syndrome is an inherited disorder affecting the heart’s electrical system. It creates abnormal electrical patterns and increases risk for dangerous heart rhythms—particularly ventricular fibrillation, where the lower chambers quiver chaotically instead of pumping blood. When this happens, blood circulation stops and you collapse within seconds. Without immediate defibrillation, ventricular fibrillation is fatal within minutes. Despite this serious risk, your heart muscle and structure are completely normal.

The condition was first described in 1992 by Spanish cardiologists Pedro and Josep Brugada. They identified a specific pattern on electrocardiograms associated with sudden death in people with structurally normal hearts.

The electrical abnormality involves sodium channels—tiny pores in heart muscle cells that control electrical signals. Genetic mutations cause these channels to malfunction, creating conditions where the heart’s electrical activity can suddenly become chaotic, triggering these fast, deadly rhythms from the lower heart chambers.

The characteristic finding is a specific pattern on electrocardiogram showing unusual changes in the right side of the heart. Three types of patterns exist, with Type 1 being most strongly associated with life-threatening events and sudden death. However, the pattern isn’t always visible—it can come and go, appearing only during fever, after certain medications, or during specific testing.

Brugada syndrome is inherited in families through genes passed from parent to child. If you have one parent with Brugada syndrome, you have a 50% chance of inheriting the genetic mutation. However, not everyone with the mutation develops symptoms or life-threatening rhythms—this is called incomplete penetrance.

The condition is more common in people of Southeast Asian descent and affects men more than women. Men with Brugada syndrome are about 8-10 times more likely to experience life-threatening rhythms than women with the same mutation.

Most dangerous events occur during rest or sleep, particularly in the early morning hours. This differs from many other heart rhythm problems that occur during exertion or stress. Fever commonly triggers events—high temperatures can unmask the electrical abnormality and precipitate deadly rhythms.

Many people with Brugada syndrome never experience symptoms and live normal lifespans. Others have sudden cardiac arrest as their first symptom, which is why identifying at-risk individuals through family screening is so important.

Causes

Brugada syndrome is caused by genetic mutations affecting proteins that control electrical signals in heart muscle cells.

• The most commonly identified mutation affects the SCN5A gene, which provides instructions for making sodium channels in heart cells. These channels allow sodium to flow into cells, creating the electrical signals that trigger heartbeats. When channels don’t work properly, electrical signals become abnormal, setting up conditions for ventricular fibrillation to occur.
• However, SCN5A mutations are found in only about 20-30% of people with Brugada syndrome. Many other genes have been implicated, and research continues to identify additional genetic causes. In many people with clear Brugada syndrome, no mutation can be found with current testing—this doesn’t mean it’s not genetic, just that we haven’t identified the responsible gene yet.
• The condition is inherited through families in a pattern where having just one abnormal gene copy (from one parent) is enough to cause disease. This means if your parent has Brugada syndrome, each of their children has a 50% chance of inheriting the mutation.
• Some people develop Brugada-like patterns without inherited mutations. Certain medications can create similar electrical abnormalities, including some drugs for abnormal rhythms, certain psychiatric medications, cocaine, and excessive alcohol. Some medical conditions including electrolyte imbalances and heart muscle inflammation can produce similar patterns.
• Fever is a major trigger for ventricular fibrillation in people with Brugada syndrome. The elevated body temperature worsens the electrical abnormality, which is why fever must be treated aggressively in affected individuals.
• Certain medications that are safe for most people can trigger life-threatening rhythms in those with Brugada syndrome. A comprehensive list is maintained at www.brugadadrugs.org, which people with the condition should consult before taking new medications.

Symptoms

Many people with Brugada syndrome have no symptoms throughout their lives. The condition is often discovered incidentally through routine electrocardiograms or during family screening after a relative is diagnosed.

• When symptoms occur, they result from ventricular fibrillation or other fast rhythms from the lower heart chambers that reduce blood flow to the brain and body. Fainting, called syncope, is a common symptom. These episodes typically occur during rest or sleep rather than during exertion. The fainting happens because your heart suddenly develops a rapid, chaotic rhythm that stops effective blood pumping. If you faint without warning, particularly at rest or upon waking, and heart rhythm problems are suspected, Brugada syndrome should be considered.
• Seizure-like activity can occur during rhythm episodes. The brain doesn’t receive adequate blood flow, causing movements that resemble seizures. This sometimes leads to misdiagnosis as epilepsy before the heart rhythm problem is identified.
• Sudden cardiac arrest is the most serious manifestation. The heart suddenly develops ventricular fibrillation—a fast, chaotic rhythm where the lower chambers quiver uselessly instead of pumping. Blood circulation stops and you collapse unconscious. Without immediate defibrillation to shock the heart back to normal rhythm, this is fatal within minutes. For some people, cardiac arrest is the first sign of Brugada syndrome.
• Palpitations—feeling your heart racing or beating irregularly—occur in some people before more serious rhythm problems develop. This might be brief episodes of rapid heartbeat that stop on their own or that progress to more dangerous rhythms.
• Gasping or labored breathing during sleep might be noticed by bed partners when rhythm problems occur at night.
• Sudden nocturnal death—dying suddenly during sleep with no apparent cause—has been associated with Brugada syndrome, particularly in Southeast Asian populations where it’s called “Sudden Unexplained Nocturnal Death Syndrome.”
• The pattern of symptoms typically appearing during rest or sleep, often in the early morning hours, is characteristic of Brugada syndrome and helps distinguish it from other heart rhythm disorders.
• Importantly, symptoms often first appear in adolescence or early adulthood, though they can occur at any age from infancy through older adulthood.

Diagnosis

Diagnosing Brugada syndrome involves identifying the characteristic electrical pattern and assessing risk for life-threatening rhythms.

• An electrocardiogram is the primary diagnostic tool. The test shows a specific pattern in leads recording from the right side of the heart. Type 1 Brugada pattern is diagnostic and consists of specific changes in how electrical signals appear on the recording.
• However, the pattern isn’t always visible. It can be intermittent, appearing and disappearing. Fever, certain medications, or changes in electrolytes can unmask the pattern. Some people require provocative testing where drugs are given to bring out the electrical abnormality if Brugada syndrome is suspected but the baseline electrocardiogram is normal.
• Drug challenge testing uses medications that temporarily worsen the electrical abnormality, making the diagnostic pattern appear. This is performed in monitored settings with resuscitation equipment immediately available since the drugs can trigger the very rhythms being screened for—ventricular fibrillation or rapid beating of the lower chambers.
• Family history is crucial. If close relatives had sudden unexplained death, particularly at young ages or during sleep, Brugada syndrome should be investigated. Family screening of first-degree relatives is recommended when anyone is diagnosed.
• Genetic testing can identify mutations in about 20-30% of people with Brugada syndrome. Finding a mutation confirms the diagnosis and allows targeted testing of family members. However, negative genetic testing doesn’t rule out the condition since many causative genes haven’t been identified.
• Extended heart monitoring with wearable devices helps determine if fast rhythms from the lower chambers are actually occurring, particularly if symptoms like fainting have happened.
• Risk stratification after diagnosis involves determining how likely you are to experience ventricular fibrillation. Factors increasing risk include history of cardiac arrest or fainting, documented fast rhythms from the lower chambers on monitors, and the presence of Type 1 pattern on electrocardiogram without needing drugs to unmask it.

Treatment

Treatment focuses on preventing sudden cardiac death in people at significant risk while avoiding unnecessary interventions in those at low risk.

• For people who’ve survived cardiac arrest or have documented episodes of ventricular fibrillation, treatment is clear—an implantable defibrillator is strongly recommended. This device continuously monitors heart rhythm and automatically delivers shocks to terminate ventricular fibrillation or other fast rhythms from the lower chambers before they cause death. The defibrillator doesn’t prevent these rhythms from occurring but ensures they don’t become fatal.
• For people with Brugada syndrome who’ve never had symptoms, treatment decisions are more complex and individualized. Risk stratification helps determine who needs a defibrillator. Those at highest risk—with history of fainting from rhythm problems or spontaneous Type 1 pattern—often receive defibrillators. Those at lower risk might be monitored without a device.
• Medications have limited role. Unlike many rhythm disorders, drugs aren’t effective at preventing ventricular fibrillation in Brugada syndrome. One medication, quinidine, shows some benefit in research studies and might be considered for people who can’t have defibrillators or who experience frequent shocks despite having devices.
• Aggressive fever reduction is crucial for everyone with Brugada syndrome. Fever lowers the threshold for ventricular fibrillation. At the first sign of fever, take fever-reducing medications promptly and contact your doctor if fever is high or persistent.
• Avoiding trigger medications is essential. A comprehensive list is maintained online, and everyone with Brugada syndrome should check this list before taking any new medication, including over-the-counter drugs.
• Avoiding excessive alcohol consumption is recommended as large amounts can trigger rhythm problems.
• Moderate exercise is generally safe—ventricular fibrillation typically occurs at rest, not during activity. However, competitive athletics at elite levels might increase risk and should be discussed with your cardiologist.
• Electrolyte balance is important. Avoid medications causing low potassium unless medically necessary.
• For people with frequent symptoms despite defibrillators, ablation procedures destroying the tissue triggering fast rhythms are being investigated but remain somewhat experimental.

What Happens If Left Untreated

The natural history of untreated Brugada syndrome varies enormously based on individual risk factors.

• For high-risk individuals—those who’ve had cardiac arrest or documented ventricular fibrillation—leaving the condition untreated means high likelihood of sudden death. Once you’ve had one episode of ventricular fibrillation, the chance of another is significant.
• For people with the electrical pattern but no symptoms, risk is lower but still present. Annual rates of cardiac arrest in this group are estimated at 0.5-1%, which may sound small but accumulates over a lifetime. A 20-year-old with Brugada syndrome faces decades of this risk.
• Sudden death typically occurs during rest or sleep without warning. The heart suddenly develops ventricular fibrillation—the lower chambers quiver chaotically instead of pumping. One moment the person appears fine, the next they’re in cardiac arrest. Without immediate defibrillation, survival is unlikely.
• The unpredictability is particularly concerning—you can’t predict when or if ventricular fibrillation will occur. Some people with Brugada syndrome live their entire lives without problems, while others experience events in their 20s or 30s.
• Family tragedy occurs when Brugada syndrome isn’t recognized. Multiple family members might die suddenly at young ages before the pattern is identified and surviving relatives screened and protected.

What to Watch For

If you have Brugada syndrome, certain situations require immediate action.

• Call emergency services immediately if you faint. Any loss of consciousness in someone with Brugada syndrome should be considered ventricular fibrillation or other serious rhythm until proven otherwise.
• Seek immediate medical attention for sustained rapid heartbeat, severe dizziness, or chest pain accompanied by feeling faint.
• If you develop high fever, take fever-reducing medication immediately and contact your doctor. Aggressive fever treatment is crucial because high temperature can trigger ventricular fibrillation.
• If you have a defibrillator and it delivers a shock, follow your doctor’s instructions. Usually this means contacting your cardiologist promptly for device interrogation to see why it fired and what rhythm it treated.
• Family members should learn CPR and know where automated external defibrillators are located in your workplace and community. Immediate bystander response with chest compressions and defibrillation dramatically improves survival from cardiac arrest.
• Inform all doctors treating you about your Brugada syndrome diagnosis. Certain medications and anesthetics used in surgery can trigger life-threatening rhythms.

Living with Brugada Syndrome

Managing Brugada syndrome involves balancing reasonable precautions with living a normal life.

• If you have a defibrillator, understand how it works and what to expect. Most people adapt well to having the device. It provides security knowing ventricular fibrillation or other dangerous rhythms will be automatically treated.
• Carry information about your condition—a card in your wallet or medical alert bracelet—so emergency personnel know about Brugada syndrome and which medications to avoid.
• Maintain a list of medications to avoid and check it before taking anything new. Share this list with all doctors and dentists treating you.
• Treat fever aggressively at the first sign. Keep fever-reducing medications at home and use them promptly.
• Regular follow-up with a cardiologist experienced in inherited rhythm disorders is important. If you have a defibrillator, it requires periodic checking.
• Inform family members about the hereditary nature of Brugada syndrome. First-degree relatives—parents, siblings, and children—should undergo screening with electrocardiograms.
• Exercise is generally encouraged. Ventricular fibrillation occurs at rest, so staying active isn’t particularly risky and promotes overall health.
• Women with Brugada syndrome can usually have successful pregnancies, though this should be discussed with both cardiologist and obstetrician. The stress of pregnancy and delivery needs careful monitoring.
• Some people with Brugada syndrome experience anxiety about sudden death, which is understandable. Support groups and counseling help many people cope with living with this condition.
• Most people with Brugada syndrome, particularly those protected by defibrillators, live normal lifespans doing essentially everything others do.

Key Points

• Brugada syndrome is an inherited electrical heart disorder that can cause sudden death despite completely normal heart structure. The problem is purely in how electrical signals behave, creating conditions for ventricular fibrillation—a chaotic rhythm where the heart quivers instead of pumping.
• Many people with the condition never have symptoms and live normal lives. Others experience sudden cardiac arrest from ventricular fibrillation, sometimes during sleep, as their first manifestation.
• The condition is diagnosed through specific patterns on electrocardiograms, though these patterns can be intermittent and sometimes require special testing to reveal.
• Family screening is crucial. If someone is diagnosed, all first-degree relatives should undergo evaluation since there’s a 50% chance they inherited the same mutation.
• Implantable defibrillators prevent sudden death in those at high risk. The device automatically shocks the heart when ventricular fibrillation or other fast rhythms from the lower chambers occur, restoring normal rhythm before they become fatal.
• Fever is a major trigger for ventricular fibrillation—it must be treated aggressively at the first sign in anyone with Brugada syndrome.
• Certain medications can trigger life-threatening rhythms and must be avoided. A comprehensive list is available online that everyone with the condition should consult.
• Ventricular fibrillation typically occurs during rest or sleep, not during exercise, which distinguishes Brugada syndrome from many other rhythm disorders.
• Men are affected more severely than women, even when both carry the same genetic mutation.
• Work with a cardiologist experienced in inherited rhythm disorders. These specialists understand risk stratification—determining who needs aggressive treatment versus who can be safely monitored—and stay current on evolving treatment approaches. While Brugada syndrome is serious, most people with the condition, particularly those with defibrillators when indicated, live full, active lives. The key is proper diagnosis, appropriate use of defibrillators in high-risk individuals, avoiding triggers, and ensuring family members are screened to identify others who might be at risk and protect them from sudden death.

Reference: Brugada Syndrome