Heart Physiology and Heart Disease

The human heart is a remarkable organ which functions on the principles of a mechanical pump through a cycle of contractions and relaxations (Lim, Circ Heart Fail 13: E007393, 2020). The main function of the heart is to provide hydraulic energy to maintain the circulation through which the body supplies nutrients and removes waste products to and from metabolising tissues (Tan, Cardiovasc Res 21: 615–622, 1987). The heart consists of four chambers: two small upper chambers called the atria and two larger lower chambers called the ventricles. These chambers are tri-layered: the outer pericardium; a double-layered semi-serous membrane, the myocardium, which contains the heart muscle responsible for pumping blood; and the inner endocardium. This chapter briefly explores the fundamental principles of cardiac physiology, the mechanisms that regulate the beating heart and the delicate balance that maintains cardiovascular health. Beyond normal functioning, this chapter also explores the profound impact of select cardiac diseases including cardiomyopathies; a diverse group of conditions that impact the heart’s muscle, challenging its ability to function optimally; coronary artery disease; the insidious process of arterial plaque formation and its catastrophic consequences on myocardial health and finally, heart failure, a condition where the heart’s resilience is tested and its ability to pump blood effectively is compromised.