Cardiac Transmembrane Ion Channels and Action Potentials: Cellular Physiology and Arrhythmogenic Behavior.

Cardiac arrhythmias are among the leading causes of mortality. They often arise from alterations in the electrophysiological properties of cardiac cells, and their underlying ionic mechanisms. It is therefore critical to further unravel the patho-physiology of the ionic basis of human cardiac electrophysiology in health and disease. In the first part of this review, current knowledge on the differences in ion channel expression and properties of the ionic processes that determine the morphology and properties of cardiac action potentials and calcium dynamics from cardiomyocytes in different regions of the heart are described. Then the cellular mechanisms promoting arrhythmias in congenital or acquired conditions of ion channel function (electrical remodelling) are discussed. The focus is human relevant findings obtained with clinical, experimental and computational studies, given that interspecies differences make the extrapolation from animal experiments to the human clinical settings difficult. Deepening the understanding of the diverse patholophysiology of human cellular electrophysiology will help developing novel and effective antiarrhythmic strategies for specific subpopulations and disease conditions.