Brugada Syndrome

Brugada syndrome is an inherited cardiac channelopathy that increases the risk of sudden cardiac death (SCD) due to supraventricular and ventricular arrhythmias, often in young, otherwise healthy individuals. The characteristic electrocardiographic (ECG) changes were first reported in the 1950s, but the syndrome was formally described in 1992 by Josep and Pedro Brugada. The syndrome is primarily identified by ECG findings of right bundle branch block and distinct ST-segment changes in the right precordial leads (V1-V3). These ECG patterns are classified into 3 morphologies. Type 1 is defined by coved ST-segment elevation of at least 2 mm in at least 1 right precordial lead, followed by T-wave inversions, in the absence of other causes of ST elevation (see . Brugada Syndrome Type 1 Morphology). Type 2 presents as saddleback-shaped ST-segment elevation of at least 2 mm, with a positive or biphasic T wave and J-point elevation of at least 1 mm. Type 3 is characterized by ST-segment elevation less than 1 mm with a positively deflecting T wave (see . Brugada Syndrome Electrocardiographic Patterns). ECG patterns observed immediately after resuscitation or electrical cardioversion should not be considered diagnostic, as the ST segment can be dynamic. Multiple patterns may appear sequentially in patients who exhibit dynamic ECG changes or are exposed to certain medications. Normal or nondiagnostic ECGs may also occur in individuals with a disease-associated genotype. Potent sodium channel-blocking drugs, including ajmaline, procainamide, and flecainide, can unmask ECG changes, although drug challenge reduces specificity. Diagnosis and management remain challenging due to an incomplete understanding of the syndrome’s genetic and molecular mechanisms. Clinical criteria continue to evolve as new research emerges.