Modeling electrical activity of the left ventricle and computational analysis of ion channels

This thesis defines a Hodgkin-Huxley type cardiac action potential (AP) model which constitutes 32 nonlinear differential equations from experimental recordings. The model includes most of the ionic currents that have been described in the literature by a new and simple definition of each of them to simulate one of the most complex systems in the body. It might provide us to investigate some diseases or some chemical material effects on the cardiac cell. To illustrate it, the model reproduces the properties of cardiac myocyte for two different AP: One is obtained by isoproterenol (ISO) substance dripped to the cell membrane, one is normal AP without making any chemical injection. The prolongation in AP after ISO induce is explained by smaller density and the slower gating kinetics of the transient outward K+ current (It0), the increasing amplitude of the rapid (IKr), the slow outward inward rectifier (IKs) currents and larger influx of Ca2+ ions. In this work, the question of how we can understand the role of each gating variable during AP is also answered by developing a new contribution analysis method. The method successfully gives the contribution of each dynamic that makes up the model without making any assumptions in the cell membrane. It has a potential to be used for large classes of dynamical systems. In the end, the new, fast, accurate dynamic clamp system is designed with a reasonable price. Dynamic clamp enables us injecting artificial ionic current generated by the model through the cell membrane using an electronic system.