Brugada

Brugada syndrome is a genetic disorder that predisposes to sudden cardiac death from rapid ventricular arrhythmias in individuals with structurally normal hearts. It was described by the Brugada brothers in 1992. The condition is most often caused by loss-of-function mutations in cardiac sodium channels, most commonly SCN5A, leading to reduced sodium current and abnormal ventricular repolarization that favors arrhythmia.

Diagnosis relies on characteristic electrocardiographic patterns. The Type 1 Brugada pattern shows a coved ST-segment elevation of at least 2 millimeters in the right precordial leads V1-V3, usually accompanied by a negative T wave. This pattern may appear spontaneously or be unmasked by sodium channel–blocking drugs during provocative testing. Types 2 and 3 patterns are less specific and require clinical criteria (history of syncope, family history of sudden death) to confirm risk.

Clinical presentation ranges from absence of symptoms to syncope or sudden death due to ventricular fibrillation. Fever, certain medications, and electrolyte disturbances can reveal or worsen the Brugada pattern. Triggers should be avoided, and patients should be managed by specialists in arrhythmia.

Management depends on risk. An implantable cardioverter-defibrillator (ICD) is the primary therapy for survivors of cardiac arrest or those with syncope from Brugada. In selected, high-risk patients without prior events, ICD may be considered. Antiarrhythmic therapy such as quinidine can reduce ventricular arrhythmias. Avoidance of drugs known to provoke Brugada patterns and aggressive fever management are important. Genetic counseling and testing may be offered, as the syndrome is inherited in an autosomal dominant pattern with incomplete penetrance.

Epidemiology and prognosis: The syndrome is relatively rare, estimated at about 0.5 to 1 per 1,000 people and more common in men and in certain regions of Southeast Asia. Prognosis varies; risk stratification relies on symptoms, ECG patterns, family history, and genetic findings, with ongoing research to refine management.