Figure 1.

Abnormal conduction in the right ventricular outflow tract (RVOT) as explanation for the Brugada syndrome. (A). The structural abnormalities (yellow) in the RVOT separate activation fronts causing fractionated unipolar electrograms. (B). The abnormalities may also set the stage for current-to-load mismatch leaving part of the myocardium unexcited. This myocardium acts as a current sink during systole and receives current from adjacent—excited—tissue causing unipolar electrograms with ST segment elevation (J-point). (C) Current-to-load mismatch may also generate unidirectional block and the onset of reentry. The lighter shade of purple in the RVOT indicates a lower conduction reserve resulting from a distinct embryonic origin [28]. RVOT, right ventricular outflow tract; RV, right ventricle; Endo, endocardium; Epi, epicardium.