What are the electrocardiogram (ECG) findings in Brugada syndrome?

From the Guidelines

Brugada syndrome on ECG is a serious condition that requires immediate attention and referral to a cardiac electrophysiologist for further evaluation and management, as it increases the risk of ventricular arrhythmias and sudden cardiac death, particularly in young adults without structural heart disease. The diagnosis of Brugada syndrome is based on a distinctive pattern in the right precordial leads (V1-V3) on ECG, showing ST-segment elevation with a coved or saddleback appearance, followed by a negative T wave, with a type 1 pattern being the most diagnostic finding, characterized by at least 2mm ST elevation with downsloping ST segment and inverted T wave in at least one right precordial lead 1. This pattern may be spontaneous or induced by sodium channel blockers like flecainide or ajmaline during provocative testing.

Key Features of Brugada Syndrome

• Inherited cardiac channelopathy
• Increases risk of ventricular arrhythmias and sudden cardiac death
• Particularly affects young adults without structural heart disease
• Diagnosis based on distinctive ECG pattern in right precordial leads (V1-V3)
• Type 1 pattern is the most diagnostic finding, with at least 2mm ST elevation and downsloping ST segment and inverted T wave in at least one right precordial lead

Management of Brugada Syndrome

• Risk stratification
• Avoidance of triggering medications
• Fever management
• Consideration of an implantable cardioverter-defibrillator (ICD) for high-risk patients, as ICD implantation has been shown to reduce mortality in symptomatic patients with Brugada syndrome 1
• Quinidine or isoproterenol may be considered in patients with Brugada syndrome to treat electrical storms, and catheter ablation may be considered in patients with a history of electrical storms or repeated appropriate ICD shocks 1

Important Considerations

• The ECG pattern can be intermittent and may be unmasked during febrile illnesses, so repeat ECGs during fever may be warranted in suspected cases
• Genetic testing may be considered, but results do not currently influence prognosis or treatment, as the yield of genetic testing in phenotype positive patients is approximately 20% to 30% in Brugada syndrome, with SCN5A variants accounting for most of this subset of genotype positive Brugada syndrome 1

From the Research

Brugada Syndrome on ECG

• Brugada syndrome is characterized by a coved ST-segment elevation in right precordial leads on an electrocardiogram (ECG) 2.
• The diagnosis of Brugada syndrome relies on the presence of a type-1 Brugada pattern on ECG, either spontaneously or following a drug provocation test using a sodium channel blocker 2.
• A correct ECG diagnosis remains challenging, and the syndrome may be unmasked in susceptible individuals by monitoring factors such as fever 2.
• The ECG pattern of Brugada syndrome is typically seen in leads V1 and V2 recorded from the 4th to 2nd intercostal spaces 3.

ECG Markers and Risk Stratification

• Several ECG markers, such as QRS fragmentation and infero-lateral early repolarization, have been demonstrated to signify increased arrhythmic risk in Brugada syndrome 3.
• However, the value of these markers still needs to be confirmed in large prospective studies 3.
• Novel risk assessment strategies, including computerized quantitative ECG analysis and combined assessment of factors of ventricular arrhythmogenesis, are being developed to identify patients at high risk of sudden cardiac death 3, 4.
• Indices incorporating both repolarization and conduction, based on the concept of excitation wavelength, have been proposed as potential markers for risk stratification in Brugada syndrome 4.

Clinical Implications and Treatment

• Brugada syndrome is associated with an increased risk of ventricular tachycardia/fibrillation, which may cause syncope or sudden cardiac death 5.
• The implantable cardioverter-defibrillator (ICD) is the only established therapy to protect against sudden cardiac death in Brugada syndrome 6, 5.
• Pharmacological therapy, such as quinidine, has been shown to be effective in preventing ventricular arrhythmias in Brugada syndrome, but is burdened by a high incidence of side effects 6.