Abstract. The Brugada syndrome is associated with increased risk of sudden cardiac death. Patients may present with signs varying from the typical coved- or saddleback type ST-segment elevation on the right precordial leads, to a transiently normal ECG recording, which makes the identification of the syndrome very difficult sometimes.

Objective. To identify masked ECG phenotypic characteristics of the Brugada syndrome, in individuals who do not present with 12-lead ECG alterations and have first degree kinship with a confirmed Brugada syndrome patient, through the use of the body surface potential mapping (BSPM).

Material and Method. The 87-lead BSPM (28 leads on the anterior chest and 59 leads on the back) of an individual with typical 12-lead ECG of Brugada syndrome, was compared with those of his 5 asymptomatic siblings (1 male), all with normal 12-lead ECGs. Mean age: 28 + 7 years, gated-LVEF: 59 + 5% and RVEF: 41 + 5%.

Results. Analysis of the right ventricle basal region, which corresponds to the area of 15 BSPM leads located between B5, B6, B7 and F5, F6 e F7, enabled quantification of electrical alterations indicative of Brugada syndrome. Important electrical alterations were found in all the 15 BSPM leads in the map of the individual with confirmed Brugada syndrome; alterations suggestive of the syndrome could be seen in 10 to 13 leads (fig.1) in the maps of his 5 asymptomatic siblings.

Conclusion. BSPM may be a good screening method to identify individuals with the Brugada syndrome, but who are asymptomatic, have normal 12-lead ECGs and positive family history.