Detecting the early onset of promising compounds' adverse effects on the cardiac function remains a challenge in the drug discovery & development process. Current model systems, essentially animal-based, have their limitations. There is an urgent and unmet need for reliable cardiac assays mimicking the complex ion-channel interactions of cardiomyocytes in the human heart. Such a solution, capable of identifying risks and revealing underlying mechanistic interactions in early drug development phases, will considerably reduce animal use, R&D time and cost to market.