While Nav1.5 dysfunctions are commonly linked to rhythm disturbances such as type 3 Long QT Syndrome (LQTS), Brugada Syndrome (BrS), Sick Sinus Syndrome (SSS), or conduction defects (Amin et al., 2010), dysfunctions of this protein have also been linked to a morphological defect (Gosselin-Badaroudine et al., 2012b). This evidence concerns the gene SCN5A and sick sinus syndrome.