What is Heart Disease?

Coronary artery disease occurs when plaque builds up along artery walls (a process called atherosclerosis, or "hardening of the arteries"), reducing the flow of blood that nourishes the heart muscle. Inside the blood vessels, a cap forms an irregular surface over the fatty plaque. If the plaque is unstable, it bursts through the cap. The body responds as it would to any other injury: it forms blood clots, which can block blood flow and cause chest pain (known as angina) or a heart attack (also called a myocardial infarction, or MI).

References
"Coronary Artery Disease,"
National Women's Health Information Center, October 2002.