Brugada syndrome
Overview
Brugada syndrome is an inherited cardiac channelopathy that most commonly affects the right ventricular outflow tract and confers a risk of malignant ventricular arrhythmia and sudden cardiac death. The electrocardiographic hallmark is a coved (type‑1) ST‑segment elevation in the right precordial leads (V1-V3).
Recognition in the emergency department is crucial because the ECG pattern is a red flag when assessing syncope, collapse or palpitations (NICE CG109).
Epidemiology and clinical presentations
Although prevalence is low, first presentation can be sudden cardiac arrest. Typical features include:
- More common in males and in certain geographic populations (for example, Southeast Asia).
- Age at presentation usually young to middle adulthood, but any age is possible.
- Presentations range from incidental ECG findings to syncope (often abrupt, sometimes nocturnal or with agonal respiration), palpitations from ventricular tachycardia, or sudden cardiac arrest.
Pathophysiology and genetics
- Most cases are caused by loss‑of‑function mutations in SCN5A (cardiac sodium channel α‑subunit); inheritance is usually autosomal dominant with variable penetrance.
- Reduced inward sodium current shortens action potentials and slows conduction, particularly in the right ventricular epicardium, creating dispersion of repolarisation and a substrate for phase‑2 reentry, polymorphic VT and VF.
- The ECG phenotype is dynamic and may be concealed; it can be unmasked or aggravated by fever, drugs/toxins, metabolic disturbances or autonomic shifts.