Compounds that enhance hERG1 currents (hERG1 activators) were more recently discovered and have been proposed as potential pharmacotherapy for congenital long QT syndrome (LQTS) and to counteract the effects of hERG1 blockers (Kang et al., 2005; Gerlach et al., 2010; Szabo et al., 2011; Sanguinetti, 2014; Mannikko et al., 2015). This evidence concerns the gene KCNH2 and familial long QT syndrome.