Ischemia is a usually temporary shortage of oxygen in a part of the body.
It can occur when an artery bringing blood to that part, such as the heart, is narrowed by spasm or disease. Ischemic heart disease includes heart attack and related heart problems caused by narrowed coronary arteries and thus less blood and oxygen reaching the heart. It's also called coronary artery disease and coronary heart disease. As many as 3 to 4 million Americans may have ischemic episodes without knowing it. These people, who have ischemia without pain, have silent ischemia.