Formulation of ATP sensitive K+ current and action potential shape in models of human ventricular myocytes

The contribution of the ATP-sensitive K⁺ (K_ATP⁺) current to the action potential is an important component of cardiac ischaemia. The purpose of this study was to investigate how the formulation of I_K(ATP) influences action potential shape and duration in the Ten Tusscher-Panfilov 2006 model of human ventricular myocytes. We compared four different I_K(ATP) formulations, which were inserted in the epicardial variant of the cell model embedded in a 2D monodomain tissue model. The results demonstrate that inserting I_K(ATP) in the cell models shortens APD as intracellular ATP concentration is reduced, consistent with experimental findings. Although the current-voltage properties of each I_K(ATP) formulation were different, each formulation had a similar effect on the properties of the tissue model.