Three dimensional electroanatomical mapping of the left branch of the conduction system. Mapping was done using the Carto 3 system (Biosense Webster). Left ventricular anatomy reconstructed during anatomical mapping; with gray the ascending aorta. Yellow dots His bundle location (the electrical signal at this level shows a sharp ample potential). Blue dots the antero-superior fascicle (the electrical signal at this level shows a sharp small potential). Green dots the postero-inferior fascicle (electrical signal at this level shows a sharp small potential). White lines the region of the postero-inferior fascicle where the ablation points were targeted.