What Is Coronary Heart Disease?
Heart disease is caused by narrowing of the coronary
arteries that feed the heart. Like any muscle, the heart
needs a constant supply of oxygen and nutrients, which
are carried to it by the blood in the coronary arteries.
When the coronary arteries become narrowed or clogged
by cholesterol and fat deposits--a process called atherosclerosis--and
cannot supply enough blood to the heart, the result
is coronary heart disease (CHD). If not enough oxygen-carrying
blood reaches the heart, you may experience chest pain
called angina. If the blood supply to a portion of the
heart is completely cut off by total blockage of a coronary
artery, the result is a heart attack. This is usually
due to a sudden closure from a blood clot forming on
top of a previous narrowing.
Cholesterol is a waxy, fat-like substance that occurs
naturally in all parts of the body and that your body
needs to function normally. It is present in cell walls
or membranes everywhere in the body, including the brain,
nerves, muscle, skin, liver, intestines, and heart.
Your body uses cholesterol to produce many hormones,
vitamin D, and the bile acids that help to digest fat.
It takes only a small amount of cholesterol in the blood
to meet these needs. If you have too much cholesterol
in your bloodstream, the excess is deposited in arteries,
including the coronary arteries, where it contributes
to the narrowing and blockages that cause the signs
and symptoms of heart disease.