Dysregulation of Ionic Homeostasis: Relevance for Cardiac Arrhythmias

Abstract

The action potential is formed by the interaction of various sarcolemmal ionic currents. These currents are produced by the flow of ions which is driven by ionic electrochemical gradient across the sarcolemma and is mediated by ion channels. Alterations in ion channel function or trans-sarcolemmal ionic electrochemical gradients lead to alteration in ionic current and action potential which can cause arrhythmias. Extracellular and intracellular concentration of some ions can modulate the gating of ion channels. Therefore, the maintenance of the correct intra- and extracellular ionic concentrations and trans-sarcolemmal ionic gradients (ionic homeostasis) is essential for the electrical function of the heart. Alterations in ionic homeostasis can lead to profound alterations in cardiac electrophysiology and arrhythmias. In this chapter will review how dysregulation of ionic homeostasis can lead to arrhythmias with a particular emphasis on channelopathies.