The most common form of heart disease is Atherosclerosis, also known as coronary heart disease or hardening of the arteries. The build-up that results, called plaque, may partially or totally block the blood's flow through the artery.
Atherosclerosis affects large and medium-sized arteries.
The type of artery and where the plaque develops varies with each person. Atherosclerosis is a slow, progressive disease that may start in childhood. Exactly how Atherosclerosis begins or what causes it isn't known, but some theories have been proposed. Many scientists think Atherosclerosis begins because the innermost layer of the artery, called the endothelium, becomes damaged. Possible causes of damage to the arterial wall are elevated levels of cholesterol and triglyceride in the blood, high blood pressure and cigarette smoke.