A minimal two state variables model for action potential in human ventricular cell

The study of cardiac arrhythmia is a great help for prevention of the major reason of human death. To study the arrhythmias, we need cell models that not only mimic AP’s normal behavior, but also show their abnormal activity. The usual electrophysiological models contain a lot of details and hence complicate mathematics which lowers the computational efficiency. In this paper, a minimal 2-state variables model is presented that not only simulates normal characteristics of human ventricular cells like excitability, AP morphology, restitution and effects of currents block, but also replicates early after depolarization (EAD) which is an abnormal activity of cardiac cells. The presented model is a conductance based one, incorporating two currents; inward and outward that delighting all the membrane inward and outward currents respectively. The adjustment and regulation of parameters were performed using an iterative algorithm that minimizes mean squares error between model responses and real APs. The effective range of parameters for initiation of the EAD is determined by the use of dynamical system analysis theory. The simulation results are in agreement with electrophysiological realities. The computing time of the model for an one-dimensional array of 10 cells is estimated to be between 34 to 112 times faster than some well-known electrophysiological models.