Cardiac myocytes are an important tool for investigating cardiac function and dysfunction. Additionally, their use is becoming increasingly important for drug safety testing. The ability to study ion channel function in both current and voltage clamp modes of the patch clamp technique is a great advantage, and to perform these experiments using an automated patch clamp device to enable higher throughput is desirable. Using stem cell derived cardiac myocytes, recordings could be made not only in the voltage clamp mode but also in the current clamp mode on a planar patch clamp workstation. This demonstrates that parallel current clamp recordings on a planar patch clamp workstation are possible. Ion channels important in drug discovery, such as hERG and voltage-gated Na+, Ca2+ and K+ channels in the voltage clamp mode from stem cell derived cardiac myocytes will be shown. In addition, action potential recordings in the current clamp mode at room temperature and modulation of the action potential by compounds such as lidocaine will be shown. Recordings could also be made at 35°C, and modulation of the action potentials by hERG active compounds, such as cisapride, will also be shown. Interestingly, some hERG-active compounds display different potencies at room temperature and at 35°C and this will be demonstrated using erythromycin on hERG expressed in HEK cells.