The hERG channel activator, RPR260243, enhances protective current early in the refractory period reducing arrhythmogenicity in zebrafish hearts.

Human ether-à-go-go related gene (hERG) K channels are important in cardiac repolarization, and their dysfunction causes prolongation of the ventricular action potential, long QT syndrome, and arrhythmia. As such, approaches to augment hERG channel function, such as activator compounds, have been of significant interest due to their marked therapeutic potential. Activator compounds that hinder channel inactivation abbreviate action potential duration (APD) but carry risk of overcorrection leading to short QT syndrome.