NCIt definition : A disorder of cardiac function caused by insufficient blood flow to the muscle tissue
of the heart. The decreased blood flow may be due to narrowing of the coronary arteries,
to obstruction by a thrombus, or less commonly, to diffuse narrowing of arterioles
and other small vessels within the heart. Severe interruption of the blood supply
to the myocardial tissue may result in necrosis of cardiac muscle (myocardial infarction).;