Ischemia is a form of coronary heart disease that occurs when fat deposits and plaque serve to narrow the interior of an artery to such a severe point that the heart is not able to receive enough oxygen-rich blood for its purposes and is therefore deprived. In as simple terms as possible, ischemia is a restriction in blood supply. What ends up happening is the heart muscle cramps. In this way then, ischemia that takes place in the heart is very much like getting a severe cramp in your leg, only cramping of the heart is more serious than cramping that occurs in the leg area.



Ischemia usually takes place when the heart is in need of an extra supply of oxygen. This is most likely to take place when there is a great deal of physical activity or exertion such as during weight training or practically any form of exercise, when a person is eating, when an individual is either very excited or under a great deal of stress and when a person is exposed to extreme temperatures, such as the very cold. Coronary artery disease can become so severe that ischemia can begin to take place even when a person is in a resting state.

Sometimes ischemia can be relieved quickly and easily and other times, or for some individuals it takes much longer. When it can be dealt with and gotten out of the way in a reasonably speedy span of time, such as within a 10 minute period with the help of either bed rest or medicine then it is sometimes given the name "stable coronary heart disease" or in other cases simply called, "stable angina."

When blood vessels are blocked or become constricted due to ischemia what takes place is angina pectoris. This condition can occur for a number of reasons. It can take place as a result of tachycardia, which is an abnormally fast heartbeat, or due to thromboembolism, which are blood clots. Angina pectoris can also take place due to atherosclerosis, which is defined as "lipid-laden plaques obstructing the lumen of arteries", and hypotension, which is the technical name for low blood pressure, which is likely to occur in cases of heart failure or septic shock.

But there are still other reasons why angina pectoris in relation to ischemia could take place. A tumor could cause outside compression or pressure on a blood vessel, which could bring about the problem. There could be foreign bodies in existence that could cause the problem, such as in the case of a pregnant woman, amniotic fluid that is in evidence within an amniotic fluid embolism. Finally angina pectoris could also occur as a result of sickle cell disease, which constitutes hemoglobin that is shaped abnormally.

Due to the fact that oxygen is connected to hemoglobin in all red blood cells, when there is an inadequate flow of blood the tissue then becomes hypoxic and in extreme cases, with no oxygen supply whatsoever, it becomes anoxic. A state of anoxic can lead to the death of cells, which is known as necrosis. When necrosis occurs as a result of ischemic it generally takes anywhere from 10 to 12 hours to occur.