The Comprehensive in vitro Proarrhythmia Assay (CiPA) initiative is a new cardiac safety testing proposal sponsored by the FDA to refine the current ICH S7B and E14 guidelines. Two components of CiPA utilise in vitro electrophysiological assays that require validation using a toolbox of compounds with defined clinical proarrhythmic risk. Here we outline our progress to optimise these electrophysiological assays to meet the CiPA goal of predicting human cardiac liability.