Electrophysiologic remodeling: are ion channels static players or dynamic movers?

Electrophysiologic remodeling refers to changes in cardiac electrophysiologic function caused by heart disease or arrhythmias. Recent work indicates that not only can ion channel abnormalities cause cardiac arrhythmias, but cardiac arrhythmias can cause ion channel abnormalities. Thus, ion channels do not only set the electrophysiologic milieu and cause arrhythmias in a static way when abnormal, but they also alter their properties in response to rhythm disorders, playing an active role in the evolution of disturbances in cardiac rhythm. This article briefly visits the concepts of electrophysiologic and ionic remodeling, and it presents some pertinent "hows," "whys," and "whats." We are only beginning to appreciate the nature and importance of these fundamental mechanisms, which undoubtedly will provide major clues to the understanding and treatment of cardiac disease and arrhythmias over the next 5 to 10 years.