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Brugada Syndrome

By

L. Brent Mitchell

, MD, Libin Cardiovascular Institute of Alberta, University of Calgary

Last review/revision Jan 2023
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Brugada syndrome is an inherited channelopathy causing an increased risk of ventricular tachycardia (VT) and ventricular fibrillation (VF) leading to syncope and sudden death.

The incidence of Brugada syndrome is approximately 1 in 1000 and is higher in people with Asian ancestry. The majority of patients with clinically apparent Brugada syndrome are male.

There are 3 patterns of Brugada syndrome, classified based on ECG parameters.

Pathophysiology of Brugada Syndrome

Brugada syndrome results from mutations that

  • Decrease inward sodium or calcium currents OR

  • Increase early outward potassium currents

These abnormalities lead to early loss of the action potential plateau, particularly in the epicardial cells of the right ventricular outflow tract that produce characteristic right precordial ECG changes and a propensity to ventricular tachyarrhythmias. Although different mutations have been reported, most are in SCN5A gene, producing a loss-of-function of the inward sodium current.

Symptoms and Signs of Brugada Syndrome

Diagnosis of Brugada Syndrome

  • Electrocardiography (ECG)

  • Family history

  • Provocative testing to induce characteristic ECG changes

  • Genetic testing

Diagnosis should be considered in patients with unexplained cardiac arrest or syncope or a family history of such when the affected people do not have structural heart disease.

Initial diagnosis of Brugada syndrome is based on a characteristic ECG pattern, the type 1 Brugada ECG pattern (see figure Type 1 Brugada ECG pattern Type 1 Brugada ECG pattern Type 1 Brugada ECG pattern ). The type 1 Brugada ECG pattern has prominent ST elevation in V1 and V2 (sometimes involving V3) that causes the QRS complex in these leads to resemble right bundle branch block Bundle Branch Block and Fascicular Block . The ST segment is coved and descends to an inverted T-wave.

Lesser degrees of these patterns (type 2 and type 3 Brugada ECG patterns) are not considered diagnostic. The type 2 and type 3 patterns may change to a type 1 pattern spontaneously, with fever, or in response to drugs. The latter is the basis of a challenge diagnostic test usually using IV ajmaline, procainamide, flecainide or pilsicainide.

The role of electrophysiologic testing is currently debated. Genetic testing is usually recommended but has a yield of approximately 20% to 30%.

Type 1 Brugada ECG pattern

Prominent J-point elevation to a coved ST segment, leading to an inverted T-wave in leads V1 and V2.

Type 1 Brugada ECG pattern

Treatment of Brugada Syndrome

  • Implantable cardioverter-defibrillator

  • Screening of family members

When frequent ICD discharges need to be suppressed, quinidine, which blocks the transient outward potassium current that may be increased in Brugada syndrome, may be efficacious. IV isoproterenol has also been used if the cause of the frequently recurrent arrhythmias appears transient and reversible.

Best treatment of Brugada syndrome in patients diagnosed based on ECG changes and family history but who do not have syncope or arrhythmia is unclear, although they do have increased risk of sudden death.

Prevention of Brugada Syndrome Arrhythmias

It is important to avoid factors that can trigger arrhythmias. Patients should monitor their temperature during infectious illness and take antipyretic therapy for fever. When possible, clinicians should stop any predisposing drugs and prescribe alternatives. Patients should avoid substances, particularly cocaine and excessive alcohol, that are arrhythmogenic in Brugada syndrome (for an up-to-date list, see www.brugadadrugs.org).

Key Points

  • Brugada syndrome is a genetic disorder causing characteristic ECG changes and an increased risk of ventricular arrhythmias causing syncope and sometimes sudden cardiac death at a relatively young age

  • Risk factors for symptomatic arrhythmias include fever, and numerous drugs, including alcohol

  • Diagnosis is by ECG, sometimes with provocative testing

  • An implantable cardioverter-defibrillator may be required

More Information

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

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