What is ischemic heart disease ???

the heart not only pumps blood all over the body to feed cells nutrients. It also pumps it to it's self. The blood vessles are all around and through out the heart tissue. They vary in size. So the smaller vessels begin to get more narrow as we age, and many nutritional factors such as cholesteral can cause this narrowing. so just as in garden hoses the smaller the hose is in diameter the less water will run through it.
well when the vessels become narrower less blood will get to that area of the heart that the effected vessel feeds. Now This decrese in blood flow causes a cellular starvation in that area of the heart and those cells can begin to die. Ultimately causing one or more areas of the heart to not work well or at all with the other uneffected areas. This ultimately results in the hearts pumping action decreasing. Then this is a loop. Then the heart does not have the pressure it once had and can have a harder time feeding other areas of the heart. so on and so on. Now if a little particle of blood that is bigger than the normal (called plaque or clot) wedges itself into one of the narrowing vessels it will prevent blood flow to the effected area. And the same will occur. so ischemic heart disease is that happening over a period of time starting little by little. Little areas of the heart difuse or isolated that are either damaged or dead cells. Hope this help. and sorry that you must be asking this question.

Ischemic heart disease is characterized by the gradual and irregular accumulation of fatty deposits along the wall of the coronary arteries (atherosclerosis). These arteries encircle the heart and provide its main supply of blood. After a while the affected vessels narrow and harden. This produces ischemia, an insufficient supply of oxygen. Ischemia damages heart muscle by causing local cell death. Without oxygen, a cell's ability to perform its electron transport functions (necessary to form ATP) is seriously impaired. Furthermore, the blockage also traps carbon dioxide, raising pH and exacerbating the problem
Ischemic heart disease=coronary insufficiency ,coronary arteries[the arterial vessels that supply the heart muscles] gets either narrowed due to atherosclerosis[narrowing and hardening of the vessels wall due deposition of cholesterol and fats in the vessel wall
or blocked due to clot formation in the lumen of vessel as the
a result of that the oxygen transport to cardiac muscles reduced and end product of metabolites accumulate in cardiac muscles
manifested clinically by cardiac pain [angina pectores] or other forms of cardiac pain and its radiation to different areas like left arm, back of chest, epigastrium. managed medically mainly by B.blocker ., coronary dilators , anti platelets like aspirin or management could be interventionally by balloon dilatation of narrowed part and stenting of the dilated part to prevent recoil
coronary dilators , or surgically by coronary bypass [ means part of vessel wall attached [anastomomsed] above and below the stenosed or blocked part of vessel wall .
sctemic colitisjsis inflammation of the intestine (colitis) caused by inadequate blood supply (ischemia) to meet the metabolic demands.
ischemia developes when blood supply (oxygen supply) to an organ does not meet the demands. the most common cause is coronary artery disease. which results in a fixed obstruction to coronary blood flow. other causes: coronary artery thrombosis, spasm or arteritis(rare).
the imbalance might be caused by increase in the heart's output as in thyrotoxicosis or myocardial hypertrophy..
saunders' pocket essentials of clinical medicine (kumar & clark) 3rd ed. p397