Repolarization abbreviation with the antiarrhythmic drug mexiletine has been found to normalize the QTc interval and reduce the rate of events in long QT syndrome type 3 (LQT3), but it is only partially efficacious in other malignant forms, including LQT2 and LQT8. There are compounds that have not been tested, such as hERG channel agonists, which are capable of shortening repolarization. The potent hERG agonist ICA-105574 was thus tested in a clinically relevant porcine model of LQT8.