A study of Icelanders has revealed that the loss of 12 letters of genetic code in a single gene substantially reduces the risk for a heart attack and also lowers cholesterol levels. Heart attacks happen when the flow of oxygen rich blood through a coronary artery to a region of the heart muscle is blocked. Without blood flow, the muscle in the deprived region of the heart will begin to die and is replaced by scar tissue resulting in permanent damage to the heart.
The most common cause of heart attacks is coronary heart disease or CHD in which there is accumulation of a waxy substance in arteries leading to a plaque. This accumulation can progress for years resulting in a condition called atherosclerosis. When plaques get big enough to block the artery, this is called ischemia. Plaques can also rupture leading to the formation of a blood clot. If the clot gets large enough, it can completely block the flow of blood.