Up to 3 ECG variants of Brugada syndrome have been described, but the main one, type 1, is associated with ST segment elevation in right precordial leads. It usually is a J point elevation with a downsloping ST segment, and the ST elevation usually tapers off going toward leads V4 to V6. Additional features that can help to differentiate it from other causes of ST elevation are: associated T wave inversion, absence of reciprocal ST depression, pseudo RBBB pattern, and normal QTc. Type 2 has a saddleback appearance with a high take-off ST-segment elevation of ≥ 2 mm followed by a trough displaying ≥ 1 mm ST elevation followed by either a positive or a biphasic T-wave. Type 3 has either a saddleback or a coved appearance with an ST-segment elevation of < 1 mm and a positive T wave. The type 2 and type 3 Brugada patterns are not specific enough to be considered diagnostic. The Brugada pattern is a dynamic ECG finding and it may not always appear on 12-lead ECG. Because the disorder is a sodium channelopathy, it usually is reproduced by sodium channel blockers. A procainamide challenge test is used to establish the diagnosis; however this test is not required if the type 1 Brugada pattern exists on the 12-lead ECG.
Because Brugada syndrome is an inherited condition, it is important to obtain a thorough family history of syncope, VT or SCD. Genetic testing of both the patient and family members for SCNA5 mutations is recommended. To establish a diagnosis of Brugada syndrome the patient should present with a type 1 Brugada ECG pattern (with or without procainamide challenge) and at least 1 of the following criteria: family history of SCD or family history of type 1 Brugada ECG change; documented VT or VF; inducibility of VT in an electrophysiology study (EPS); syncope or nocturnal agonal respiration.
© 2007 Medscape
Cite this: ST Segment Elevation on Electrocardiogram: The Electrocardiographic Pattern of Brugada Syndrome - Medscape - Sep 20, 2007.