Brugada syndrome

Brugada syndrome is primarily genetic, with an autosomal dominant mode of inheritance in most cases. This means that a single mutated gene inherited from one parent is enough to develop the disease.

Genetic Causes:
In about 20–30% of cases, a mutation in the SCN5A gene, which encodes the cardiac sodium channel, is identified. This channel plays a crucial role in allowing sodium ions to enter heart cells, a vital step in generating the action potential that leads to heart contractions.

Today, over 20 different genes have been linked to Brugada syndrome, but SCN5A mutations remain the most frequent. However, in many patients, no genetic mutation is identified, suggesting that other mechanisms or undiscovered genes may be involved.

Modulating Factors:
Several factors can exacerbate or reveal a previously silent Brugada syndrome:

• Fever: a major trigger for arrhythmias, especially in children;
• Certain medications: including Class IA and IC antiarrhythmics, tricyclic antidepressants, and some anesthetics;
• Excessive alcohol consumption;
• Electrolyte imbalances (e.g., low potassium or high calcium levels);
• High vagal tone, particularly during sleep.

These factors can influence the activity of already weakened ion channels, increasing the risk of cardiac arrhythmias.

In the vast majority of cases, Brugada syndrome remains completely asymptomatic throughout life. However, some patients with severe forms may experience heart rhythm disturbances.

These are often serious ventricular rhythm disorders (ventricular tachycardia or ventricular fibrillation), which can present as:

• Palpitations;
• Fainting spells or unexplained loss of consciousness (syncope);
• In severe cases, cardiac arrest (sudden death).

These “rhythm accidents” often occur under specific conditions:

• Taking a contraindicated medication;
• Fever episodes;
• Excessive alcohol consumption;
• During sleep or at rest (due to increased vagal tone).
• Brugada syndrome is more common in men (male-to-female ratio of 8:1), with clinical manifestations typically occurring in adulthood, peaking between ages 30 and 40.

Main Diagnostic Methods:
The electrocardiogram (ECG) — often referred to as a Brugada ECG when it reveals typical Type 1 abnormalities — is the first-line and most common diagnostic test. A definitive diagnosis can only be made if the ECG shows typical features.

A patient with Brugada syndrome may present various ECG abnormalities:

Type 1 (Diagnostic): Elevation of the ST segment ≥ 2 mm (0.2 mV) with a coved pattern followed by an inverted T wave in at least one right precordial lead (V1–V3);

Type 2 (Suspicious): ST elevation ≥ 0.5 mm with a saddleback pattern followed by a positive or biphasic T wave;

No abnormalities (normal ECG).

Only a Type 1 pattern confirms the diagnosis. For intermediate forms (Type 2), which may represent a mild form of the disease or a normal variant, a pharmacological challenge test is often used.

Additional Tests:
The pharmacological challenge with ajmaline (or sometimes flecainide) is performed in a hospital under medical supervision. This involves administering an antiarrhythmic drug intravenously to block sodium channels while continuously monitoring the ECG.

This test can unmask a Type 1 Brugada ECG pattern in patients with initially suspicious but non-diagnostic findings (Type 2). At Rythmopôle Paris, this procedure is carried out at the Institut Mutualiste Montsouris (14th arrondissement).

Genetic testing may also be offered but is only performed under two circumstances:

After a Brugada syndrome diagnosis, to identify the causal mutation;

As part of family screening, to identify carriers of the mutation among relatives.

These genetic tests are coordinated by the rhythmologists at Cardiopôle Yvart (15th arrondissement, Paris), who offer dedicated cardio-genetic consultations.

Risk assessment for severe cardiac events is crucial in determining the management strategy. Several factors are considered:

• Clinical history: Unexplained syncope, ventricular fibrillation, or resuscitated cardiac arrest are the strongest risk factors;
• ECG findings: A spontaneous Type 1 pattern carries a higher risk than one revealed only through a drug challenge;
• Sex: Men are at higher risk than women;
• Family history: Sudden cardiac death, especially before age 45, increases risk;
• Genetic findings: Particularly mutations in the SCN5A gene.

Additional tests may help refine risk stratification:

• Holter ECG monitoring to detect intermittent arrhythmias;
• Invasive electrophysiological study, sometimes used to evaluate ventricular vulnerability in select patients.

This comprehensive risk evaluation is conducted by experienced rhythmologists at Rythmopôle Paris, allowing for a personalized management strategy.

Main Treatments:
There is no curative treatment for Brugada syndrome. Management focuses on preventing life-threatening arrhythmias and sudden cardiac death:

Implantable Cardioverter Defibrillator (ICD): The only proven treatment for preventing sudden death in high-risk patients. This device continuously monitors the heart rhythm and delivers an electric shock if a dangerous arrhythmia occurs. ICD implantation is performed at the Institut Mutualiste Montsouris by Rythmopôle Paris rhythmologists. It is reserved for a small subset of patients with the highest risk;

Quinidine therapy: This antiarrhythmic drug may be offered in specific situations, such as patients with electrical storms or as an alternative to ICD implantation in selected individuals;

Radiofrequency ablation: An emerging technique aimed at eliminating areas of the heart muscle responsible for initiating arrhythmias. It may be considered for patients experiencing repeated ICD shocks despite optimal medical therapy.

Recommended Medical Follow-Up:
Regular follow-up with a rhythmologist is essential:

Rhythmology consultations every 6 to 12 months;

Device checks for patients with an ICD;

Routine ECGs;

Periodic re-evaluation of arrhythmic risk;

Adaptation of recommendations as new knowledge emerges.

Follow-up is provided at various Rythmopôle Paris centers, including Cardiopôle Peupliers-Trubert, which has specialized equipment for device checks.

Preventive Measures:

Avoiding triggers:

Limit excessive alcohol consumption;

Promptly treat fever with paracetamol, regardless of cause;

Avoid contraindicated medications (updated list available at brugadadrugs.org).

Genetic and family screening:
As a genetic disease, Brugada syndrome requires testing to identify the responsible mutation. Once identified, family members can undergo testing, enabling early diagnosis and optimized follow-up.

Physical Activity:
Activity recommendations are generally less restrictive than for other channelopathies:

Regular, moderate physical activity is encouraged for most patients;

High-level competitive sports are not systematically contraindicated but require an individualized risk assessment;

Situations promoting dehydration or significant hyperthermia (e.g., saunas, steam rooms) should be avoided;

Personalized recommendations are provided at the Centre Cœur et Santé Bernoulli (8th arrondissement, Paris).

Professional Life:
Most patients can continue working without restrictions. However, some occupations may be limited based on individual risk:

Jobs with high risk in the event of fainting (e.g., working at heights, professional driving, piloting aircraft);

Jobs with extreme environmental conditions;

High-stress professions or irregular work hours.

Pregnancy and Family Life:
For women with Brugada syndrome:

Pregnancy is generally well tolerated, as female hormones provide some protection against arrhythmias;

Specific rhythmology monitoring is recommended during pregnancy and childbirth;

Coordination between rhythmologist and obstetrician is essential for planning delivery, particularly regarding anesthesia choices;

Genetic counseling is recommended for couples considering having children, given the 50% transmission risk if a mutation is identified.

With appropriate, personalized management, the vast majority of Brugada syndrome patients can lead active lives. Educating patients and their families about preventive measures and warning signs is essential to reducing the risk of complications.

Rythmopôle Paris offers specific expertise in managing Brugada syndrome:

• A team of rhythmologists specializing in diagnosing and managing cardiac channelopathies;
• A comprehensive technical platform for performing specific diagnostic tests, including the ajmaline challenge;
• The ability to perform invasive electrophysiological studies at the Institut Mutualiste Montsouris;
• A dedicated cardio-genetic consultation at Cardiopôle Yvart for organizing genetic testing and family screening;
• Personalized follow-up, including ICD monitoring at several locations in the Paris region, such as Cardiopôle Peupliers-Trubert;
• A multidisciplinary approach, integrating tailored recommendations on physical activity and daily life;
• Close coordination with national reference centers for rare hereditary rhythm disorders.