Epikard

The epicardium, also known as the visceral pericardium, is the thin, outermost layer of the heart wall that covers the myocardium. It is the inner layer of the serous pericardium and lies against the heart, with a sliver of pericardial fluid separating it from the parietal layer of the serous pericardium. Together with the pericardium, it forms the pericardial cavity.

Structurally, the epicardium consists mainly of a layer of mesothelial cells supported by connective tissue. In some regions it contains adipose tissue, especially along the coronary sulci. Vessels, including the coronary arteries and veins, as well as autonomic nerves, run within the epicardial layer before penetrating the myocardium.

Developmentally, epicardial cells derive from the mesothelium and contribute to various cardiac structures through a process known as epithelial-to-mesenchymal transition. These cells participate in the formation of coronary vessels and connective tissue within the heart.

Functionally, the epicardium provides a protective covering and produces a lubricating serous fluid as part of the serous pericardium. The epicardial adipose tissue serves as an energy reservoir and an endocrine organ, secreting adipokines that may influence myocardial metabolism and inflammation. The epicardium also helps support coronary vessel growth and myocardial regeneration processes in development and, to a lesser extent, in adults.

Clinically, imaging measurements of epicardial fat thickness can reflect overall cardiometabolic risk and may be evaluated in conjunction with other cardiovascular assessments. Epikarditis is a rare inflammation of the epicardial layer, generally associated with pericarditis.

Etymology: from Greek epi- upon and kardia heart.

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