Brugada syndrome is a rare genetic disorder, first identified in 1992, which results in a “purely electrical” dysfunction of the heart. It is marked by abnormalities on the electrocardiogram, which are present to varying extents, and an increased risk of cardiac arrest due to ventricular fibrillation.This disorder primarily affects men and is usually diagnosed in adulthood.
What is an electrocardiogram?
It is a test that records the heart’s electrical activity over a given period of time. It identifies the speed at which the heart is beating (heart rate), whether it is beating normally (heart rhythm) and the effectiveness of the heart muscle. An electrocardiogram is also called an ECG or EKG.
Causes
By definition, people with Brugada syndrome have structurally normal hearts that contract properly and have typical morphology. The syndrome is responsible for a “purely electrical” dysfunction of the heart.
This genetic disorder can be transmitted to children if one of the parents carries the syndrome. The abnormal gene can be transmitted to children with a 50% risk of each child, both girls and boys, developing this disorder. The mutation of the “SCN5A” gene is responsible for disrupting the electrical activity of heart cells. However, not all genes associated with the syndrome have been identified.
Important Information
Family screening is crucial once the condition is known. The first consequence of Brugada syndrome is cardiac arrest. This justifies the need to identify all of the patient’s family members who might be at risk
Brugada syndrome is transmitted but not the associated risk. The risk is unique to each person.
Symptoms
Symptoms are variable and rare, making the syndrome difficult to diagnose.
The majority of people with the syndrome do not have any symptoms. In other words, they do not experience shortness of breath or any noticeable pain.
When people do experience symptoms, they are caused by heart rhythm problems, such as palpitations, dizziness or loss of consciousness.
The symptoms primarily occur at rest or at night. They can result in unexplained urinary incontinence in adults and can be triggered by a fever.
Diagnosis
The diagnosis is based on an electrocardiogram. This can be sufficient if the typical abnormalities of the syndrome are visible.
However, due to the variability of an ECG over hours and days, it cannot always detect the disease. It has now been shown that the abnormalities can be intermittent. This means that the ECG may appear entirely normal at times, even for someone with Brugada syndrome.
Physicians sometimes perform a pharmacological test to supplement the assessment, especially for family screenings. The patient receives an injection (ajmaline or flecainide in France) to reveal the typical abnormalities on the electrocardiogram. This test is performed during outpatient hospitalization to enable constant monitoring of the ECG for a few hours.
At the end of this test, the diagnosis of Brugada syndrome will either be confirmed or ruled out.
If Brugada syndrome is identified, based solely on an ECG or after a pharmacological test, it is then necessary to exclude any causes that might mimic ECG abnormalities (certain medications, heart disease or blood tests abnormalities). It is also important to confirm the heart’s normal structure by performing at least one cardiac ultrasound.
Treatment
An implanted cardioverter-defibrillator is suggested for patients who have had fainted or survived sudden death associated with Brugada syndrome. Once the defibrillator is implanted, it will need to be regularly monitored, possibly via a telemonitoring system.
Useful information
Implantable cardioverter-defibrillators continuously monitor the heart rhythm and automatically deliver an electric shock if an abnormal rhythm is detected. The shock helps “resynchronize” the heartbeat, allowing for effective heart contractions and restoring a regular rhythm.
Other alternatives may be considered if the defibrillator produces too many electric shocks:
- anti-arrhythmic medication: this type of medication is designed to stabilize the heart rhythm and prevent episodes of ventricular fibrillation;
- In rare cases, intra-cardiac catheter ablation can be performed on the areas responsible for heart rhythm disorders.
Patients without symptoms have a much lower risk of sudden cardiac death. Therefore, in most cases, implanting a cardioverter-defibrillator is not necessary. The appearance of symptoms should be monitored and reported to a physician. Follow-up electrocardiograms may also be performed.
It is important to actively treat fevers and avoid taking certain medications that trigger heart rhythm disorders.
There is not currently any standard treatment, since each patient receives personalized adjustments.
Reviewed and approved by Frédéric Sacher, Professor, MD, PhD, Cardiologist at Bordeaux University Hospital (CHU)
