Additionally, certain drugs, such as nifekalant and amiodarone, not only block hERG but also exhibit secondary effects on hERG current, such as “facilitation” that increases channel current potentials close to the threshold for channel activation (Hosaka et al., 2007; Furutani et al., 2011; Yamakawa et al., 2012) and has been postulated to lower risk for arrhythmia, complicating the cardiotoxicity assessment of the drugs. The gene discussed is KCNH2; the disease is cardiac arrhythmia.