SCN5A and long QT syndrome 3: ,9 Recently, Bezzerides and colleagues9 provided a proof of concept for a SGK1 inhibitor (SGK1-I)–based therapeutic for LQT3 by demonstration of an APD-shortening effect on a patient-specific induced pluripotent stem cell–derived cardiomyocyte (iPSC-CM) model of the LQT3-causing SCN5A-N406K variant following treatment with a novel SGK1-I.9