SCN5A mutations also play a pivotal role in complex electrophysiological disorders that present a combination of alterations, particularly on conduction disorders associated with sick sinus syndrome, atrial fibrillation and ventricular tachycardia [435]; LQT and BrS [452]; atrial fibrillation, BrS, and sudden cardiac death [394]; BrS [453]; BrS and AF [454]; or atrial arrhythmias [392]. Here, SCN5A is linked to sick sinus syndrome.