Brugada syndrome

What Is Brugada Syndrome & What Causes It?

Brugada syndrome is a heart condition where your heart beats irregularly in its lower chambers (ventricular arrhythmia). As a result, your heart cannot properly pump blood around the body, meaning it can cause serious complications and even death. 

Abnormalities in the ion channels of your heart cause the irregular heartbeat (ventricular arrhythmia). These ion channels are critical in creating the electrical impulses that tell your heart to beat. However, because of these ion channel defects, an abnormal heartbeat is triggered. 

While there are other heart conditions that cause ventricular arrhythmia, Brugada syndrome is different in that it is characterised by the irregular heartbeats occurring when you are resting or asleep. This means that there can be little to no warning of a potential cardiac arrest, and makes it likely that you will be unaware that you have the condition. 

Brugada syndrome is an important cause of sudden unexplained death, and in particular is important in people who have died and have no evidence of heart disease before death, or after death through autopsy. It is also one of the leading inherited cardiac causes of sudden death in people under 40. This is why it is so important to establish as early a diagnosis as possible. Looking into your family history, including examining any cases of sudden unexplained nocturnal death syndrome (SUNDS), can help with this.

The genetic mutation that leads to Brugada syndrome can be inherited. It is an autosomal dominant genetic disorder, meaning that if one of your parents has the condition, there is a 50% chance that you will inherit it. 

However, it is also possible that the mutations to the genes that cause Brugada syndrome can independently develop when you are conceived (we call this a de novo mutation). Therefore, there may not be any family history of the condition but you can still have the genetic mutations.

Regardless of whether you inherited the condition from your parents or the mutation occurred spontaneously, you are at risk of developing the syndrome from birth and can never entirely remove the possibility of doing so. Further, you cannot reverse the mutation. What you can do though is pursue genetic testing to reveal if you have the condition. This can confirm a Brugada syndrome diagnosis for you, allowing for swift treatment and management which can improve life expectancy and quality of life.

However, like some other heart diseases, the electrical changes of Brugada syndrome can also be acquired. This is called a ‘Brugada pattern’ ECG without the full-blown syndrome. Therefore, even if you have no family history of the disease, incidents in your life can cause the electrical abnormalities to develop. This includes:

• Types of medications that alter heart rhythms, like those to treat angina (chest pain) or high blood pressure (antihypertensives). 
• Extremely high blood levels of calcium (hypercalcemia) or potassium (hyperkalemia), which are minerals that help transmit electrical signals throughout the body, so higher levels can interfere with the electrical signals that tell your heart to beat. 
• High temperature or fever (pyrexia)
• Unusually low potassium levels (hypokalemia) will also have the same effect. 
• Structural heart abnormalities including a heart attack and cardiomyopathy.

Therefore, it is important to complete follow-up appointments with your physician if you are prescribed new medications, as well as to attend regular check-ups to ensure that your health is as it should be. You can then catch Brugada syndrome in its early stages and begin treating the condition and, if possible, minimise the conditions that can exacerbate the syndrome.

Do You Have Brugada Syndrome Symptoms?

While Brugada syndrome tends to affect you when you are asleep or at rest, you may still notice symptoms afterwards or throughout the rest of your day. 

These can include:

• Lightheadedness or fainting (syncope)
• Nightmares and/or thrashing at night noticed by your partner
• Arrhythmias, including atrial fibrillation, ventricular fibrillation and ventricular tachycardia 
• Cardiac arrest or heart attack, particularly when sleeping or at rest

You may, however, not develop any of these symptoms until later in life, with some people being asymptomatic until the 40’s and even their mid-50s. Additionally, it is possible for a person to be asymptomatic despite having the condition, including the ventricular arrhythmia showing up on an ECG. In these instances, a sudden cardiac attack or sudden death may be the first and only symptoms of the condition. Like other genetic heart diseases, Brugada syndrome can vary between individuals, even those in the same family.

Therefore, it is important that you generally look after your health, including regularly visiting your general practitioner or cardiologist for check-ups. Further, examining your family history for these signs or symptoms can help you better understand your own health, as well as that of your loved ones. You can then begin investigating if a Brugada syndrome diagnosis is right for you, which in turn is encouragement for other family members to check if they have the condition also. You can help look after them by caring for your own health.

How Is Brugada Syndrome Diagnosed?

Brugada syndrome causes a distinctive heart rhythm pattern. This means it is typically diagnosed through an ECG (electrocardiogram). However, there are instances where it has been misdiagnosed as other disorders due to shared characteristics. Similarly, the pattern can be intermittent, making it harder to pick up on an ECG. Therefore, an accurate Brugada syndrome diagnosis should rely on other elements of clinical presentation.

These can include reported symptoms, like fainting or unexplained cardiac events. Additionally, your family’s health history of events like these may indicate that genetic inheritance is at play. 

Blood tests can also help create a clearer picture. Your potassium and calcium levels can be measured to determine if acquired Brugada syndrome is likely. Additionally, your CK-MB and troponin levels can be analysed. These are the chemicals that rise for a time after chest pain starts with troponin staying elevated for up to two weeks. Therefore, even if you are having chest pain at night while asleep and unaware of it, blood tests can reveal that it is happening.

If you have genetically inherited Brugada syndrome, genetic testing can also be helpful. This can confirm your diagnosis by examining if the mutations that cause the condition are present in your genetic makeup. All that’s needed is blood or saliva to test.

Working with a cardiovascular genetics service will help ensure that your confirmed diagnosis is accurate. This is because they will truly understand how nuanced cardiac genetics can be, from the seriousness of the condition to how Brugada syndrome can differ between people. With this knowledge, they can recommend the most appropriate genetic tests and interpret them to understand if and how Brugada syndrome is affecting you.

Once you have your diagnosis, you can begin treatment as soon as possible. This will help limit and prevent further risks and complications to your heart health. 

How Genetic Testing Can Help

Genetic testing forms part of a thorough medical evaluation for Brugada syndrome. Through genetic testing, it is possible to identify the mutation that has led to the disease. With this knowledge, appropriate treatment and management plans can be tailored.

Additionally, if you are diagnosed with genetically inherited Brugada syndrome, you can encourage other family members to look into their own heart health. This can help them get an early diagnosis and protect them.