What is Brugada syndrome?

From the Guidelines

Brugada syndrome should be diagnosed and managed according to the 2015 ESC guidelines, which recommend a diagnosis based on ST-segment elevation with type 1 morphology ≥2 mm in one or more leads among the right precordial leads V1 and/or V2, and treatment with ICD implantation in high-risk patients, as well as lifestyle changes to avoid triggers such as excessive alcohol intake and large meals 1.

Diagnosis and Treatment

The diagnosis of Brugada syndrome is based on specific ECG patterns, and the condition is more common in men and people of Asian descent, particularly those from Southeast Asia. Patients may be asymptomatic or experience symptoms like fainting, palpitations, or cardiac arrest, typically during rest or sleep.

• The 2015 ESC guidelines recommend ICD implantation in patients with a diagnosis of Brugada syndrome who are survivors of an aborted cardiac arrest and/or have documented spontaneous sustained VT 1.
• The guidelines also recommend considering ICD implantation in patients with a spontaneous diagnostic type I ECG pattern and history of syncope 1.
• Additionally, quinidine or isoproterenol should be considered in patients with Brugada syndrome to treat electrical storms, as recommended by the 2017 AHA/ACC/HRS guideline 1.

Risk Stratification and Lifestyle Changes

Risk stratification is crucial in managing Brugada syndrome, with factors like previous cardiac arrest, spontaneous ECG pattern, and family history of sudden death considered.

• Patients should avoid triggers like high fever, excessive alcohol consumption, and certain medications, with prompt fever management using antipyretics like acetaminophen recommended 1.
• The 2015 ESC guidelines also recommend avoiding drugs that may induce ST-segment elevation in right precordial leads, and avoiding excessive alcohol intake and large meals 1.

Genetic Testing and Family Screening

Genetic testing can identify mutations in the SCN5A gene, which accounts for about 20-30% of cases.

• The 2017 AHA/ACC/HRS guideline recommends genetic counseling and genetic testing in patients with suspected or established Brugada syndrome to facilitate cascade screening of relatives 1.
• Family screening is essential since the condition follows an autosomal dominant inheritance pattern.

From the Research

Definition and Diagnosis of Brugada Syndrome

• Brugada syndrome is a hereditary arrhythmic syndrome that can cause sudden cardiac death (SCD) in individuals without overt structural heart disease 2.
• The diagnosis of Brugada syndrome is mainly based on the presence of a spontaneous or Na+-channel blocker induced "type 1" Brugada electrocardiographic (ECG) pattern typically seen in leads V1 and V2 recorded from the 4th to 2nd intercostal spaces 2.

Risk Stratification and Treatment

• Current guidelines recommend implantable cardioverter-defibrillator (ICD) implantation in patients with a Brugada type 1 ECG pattern if they have suffered a previous resuscitated cardiac arrest or if they have syncope of presumed cardiac origin 3.
• Asymptomatic patients with Brugada syndrome are at increased risk (0.5%-1.5%) for SCD compared to the general population, and ICD placement can reduce mortality in select asymptomatic patients 4.
• Risk factors that increase the likelihood of SCD in asymptomatic patients include an ECG demonstrating spontaneous type 1 Brugada Syndrome and inducibility of ventricular tachyarrhythmias during electrophysiological study 4.

Pharmacological Therapy

• Quinidine therapy has been shown to be effective in preventing ventricular arrhythmias (VA) in Brugada syndrome, but it is burdened by a high incidence of side effects 5.
• Other pharmacologic therapies, such as isoproterenol, cilostazol, and milrinone, can be used to abort electrical storms or as an adjunct or alternative to device therapy 6.

Clinical Implications and Management

• The majority of Brugada syndrome patients are asymptomatic when diagnosed and have generally low risk (0.5 % annually or lower), and therefore are not indicated for ICD 2.
• Novel risk assessment strategies need to be developed based on computerised quantitative ECG analysis of large digital ECG databases in patients with Brugada syndrome and their relatives, and combined assessment of the most important factors of ventricular arrhythmogenesis 2.
• Radiofrequency ablation of the right ventricular outflow tract epicardium of patients with Brugada syndrome has recently been shown to reduce arrhythmia vulnerability and the electrocardiographic manifestation of the disease 6.