subendocardiale

Subendocardial refers to the region of the heart located just beneath the endocardium, the innermost lining of the heart chambers. In the ventricular wall, the subendocardial zone lies in the inner portion of the myocardium and is distinguished from the subepicardial and midmyocardial layers. The Purkinje fiber network, an important component of the heart’s conduction system, is situated in this region, contributing to its electrical and functional properties.

Anatomically, the subendocardial layer sits closest to the blood-filled chambers and is supplied by penetrating branches of the coronary arteries. Because it endures high wall stress during systole and is relatively distant from epicardial coronary arteries, this area is particularly vulnerable to ischemia, especially under conditions of reduced coronary perfusion or increased oxygen demand.

Pathophysiologically, ischemic injury often begins in the subendocardial region and may remain confined there (subendocardial ischemia) or extend outward to become a transmural infarction that involves the full thickness of the wall. Clinically, subendocardial ischemia frequently presents with ST-segment depression and T-wave changes on electrocardiography, whereas transmural infarction typically produces ST-segment elevation.

Diagnosis and imaging can reveal a subendocardial pattern of damage. Cardiac magnetic resonance imaging with late gadolinium enhancement can show subendocardial infarction limited to inner myocardial layers, while other modalities may identify the underlying coronary disease or global perfusion deficits contributing to the condition.

See also: endocardium, myocardium, Purkinje fibers, myocardial infarction, ischemia, electrocardiography.