Calcium signaling refers to a process that involves the use of calcium ions for communicating and facilitating intracellular processes, which are necessary for signal transduction. Calcium is essential for the pumping function and electrical activity of the heart. Each time the heart beats, calcium ions enter the heart muscle cells and contribute to the electrical signal, which coordinates the functioning of the heart. Additionally, calcium ions bind to cellular machinery that aids cell contraction, enabling the heart to pump blood. Heart rhythm abnormalities (arrhythmias) are a set of heart diseases that can result from malfunctions in the calcium-controlling doors resulting in abnormal electrical signals. A healthy a heart closely regulates calcium ion signals, and the abnormalities in the calcium ion handling proteins are a crucial feature of heart diseases. Impaired calcium regulation may negatively impact the heart relaxation and pumping function, which in turn leads to various heart diseases. This book explores all the important aspects of cardiology in the present day scenario. It attempts to understand the various interventions used to manage heart diseases.