The cardiovascular system is made up of the heart and blood vessels. Blood is pumped by the heart and circulated throughout the body through the blood vessels.
Cardiovascular disease is the leading health problem in the Western world.
It is the number one cause of death in the United States, claiming more than 1 million lives annually. An estimated 50 million Americans are afflicted with heart and blood vessel disease, although many do not know it because they have no symptoms. The arteries that supply blood to the heart are called the coronararteries. If the heart's blood vessels narrow, the amount of blood they supply to the heart may be insuffi-cient to provide the oxygen the heart needs. This oxygen deprivation is what causes a type of chest pain known as angina pectoris.