Patient P., 50 years old, male, with type I Brugada syndrome was examined. The patient had aborted sudden death event (2006) in his clinical history, ICD Gem III VR was implanted in 2006, ICDLumax DR was reimplanted in 2012. The patient had coved type pattern in right precordial ECG-leads. The p.E553X mutation in SCN5A gene, whish encodes the sodium channel α-subunit, was found. Noninvasive electrocardiographic mapping was performed. Significant changes of local unipolar electrograms including QRS fragmentation, ST segment elevation and late ventricular potentials were identified in the epicardium of the right ventricle outflow tract. Thus, the presented case demonstrates that noninvasive electrocardiographic mapping methodology allows to determine and visualize arrhythmogenic substrate in patients with inherited channelopathies.