Yang et al. [27] showed that chronic exposure to azithromycin led to polymorph ventricular tachycardia without QT prolongation through altering the cardiac Na+ current and promoting loading of intracellular Na+ in the human embryonic kidney (HEK 293) and Chinese hamster ovary cells where human Na+ channels (SCN5A) heterologously expressed. Here, SCN5A is linked to polymorphic ventricular tachycardia.