Genetic defects, ionic currents and electrocardiographic alterations

Most experimental data on the kinetic properties of cardiac ion channels and their modification by genetic defects have been obtained in expression systems (e.g., Xenopus oocyte), away from the cellular environment where these channels function to generate the cardiac action potential. In this article, we describe the use of computational biology (computer simulations) in integrating such information on single ion channels into models of the functioning cardiac cell. We use this approach to mechanistically relate molecular processes to whole-cell electrophysiological function and its manifestation in electrocardiographs waveforms. Examples are provided from the congenital long QT syndrome and the Brugada syndrome.