The Food and Drug Administration (FDA) is announcing the availability of a guidance entitled "S7B Nonclinical Evaluation of the Potential for Delayed Ventricular Repolarization (QT Interval Prolongation) by Human Pharmaceuticals." The guidance was prepared under the auspices of the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH). The guidance describes a nonclinical testing strategy for assessing the potential of a test substance to delay ventricular repolarization and includes information concerning nonclinical assays and an integrated risk assessment. The guidance is intended to facilitate the nonclinical assessment of the effects of pharmaceuticals on ventricular repolarization and proarrhythmic risk.