Calcium Handling Defects and Cardiac Arrhythmia Syndromes

Abstract

Calcium ions (Ca²⁺) play a major role in the cardiac excitation-contraction coupling. Intracellular Ca²⁺ concentration increases during systole and falls in diastole thereby determining cardiac contraction and relaxation. Normal cardiac function also requires perfect organization of the ion currents at the cellular level to drive action potentials and to maintain action potential propagation and electrical homogeneity at the tissue level. Any imbalance in Ca²⁺ homeostasis of a cardiac myocyte can lead to electrical disturbances. This review aims to discuss cardiac physiology and pathophysiology from the elementary membrane processes that can cause the electrical instability of the ventricular myocytes through intracellular Ca²⁺ handling maladies to inherited and acquired arrhythmias. Finally, the paper will discuss the current therapeutic approaches targeting cardiac arrhythmias.

Keywords: atrial fibrillation; calcium signalling; cardiac arrhythmias; catecholaminergic polymorphic ventricular tachycardia; delayed afterdepolarization; early afterdepolarization; long QT syndrome; reentry.