Cardiac muscle (also called heart muscle or myocardium) is one of three types of vertebrate muscles, with the other two being skeletal and smooth muscles. It is an involuntary, striated muscle that constitutes the main tissue of the walls of the heart. The myocardium forms a thick middle layer between the outer layer of the heart wall (the epicardium) and the inner layer (the endocardium), with blood supplied via the coronary circulation. It is composed of individual heart muscle cells (cardiomyocytes) joined together by intercalated discs, encased by collagen fibres and other substances forming the extracellular matrix.
Cardiac muscle contracts in a similar manner to skeletal muscle, although with some important differences. An electrical stimulation in the form of an action potential delivered in a rhythmic pattern triggers the release of calcium from the cells internal calcium store, the sarcoplasmic reticulum. The rise in calcium causes the cells myofilaments to slide past each other in a process called excitation contraction coupling.
Diseases of heart muscle are of major importance. These include conditions caused by a restricted blood supply to the muscle including angina pectoris and myocardial infarction, and other heart muscle disease known as cardiomyopathies.
Cardiology research Journals like Clinical Cardiology and Cardiovascular Medicine (CCCM) provides a global open access platform to put forth the ongoing research, reviews and techniques related to Cardiac Muscle.