Ischaemic (or ischemic) heart disease is characterized by the reduced blood supply to the heart and constitutes the most common cause of death in most western countries.
The word ‘Ischaemia’ means a “reduced blood supply“.
The coronary arteries supply blood to the heart, there is no alternative blood supply, therefore, a blockage in the coronary arteries will reduce the supply of blood.
Most ischaemic heart disease is caused by atherosclerosis, usually, present even when the artery lumens appear normal by angiography. Initially, there is sudden severe narrowing or closure of either the large coronary arteries and/or of coronary artery end branches by debris showering downstream in the flowing blood. It is usually felt as angina, especially if a large area is affected.
The narrowing or closure is predominantly caused by the covering of atheromatous plaques within the wall of the artery rupturing, in turn leading to a heart attack (Heart attacks caused by just artery narrowing are rare). A heart attack causes damage to