KCNH2 and familial long QT syndrome: Finally, investigation of drug interactions with mutant HERG channels in LQTS using patient-specific human-induced pluripotent stem cell–derived cardiac myocytes (hiPSC-CMs) implicated that peroxisome proliferator-activated receptor-delta (PPARδ) agonists may exert indirect effects on mutant HERG channel activity by inducing 14–3-3ε expression changes, but no direct data in support of this role was investigated [19].