What Is Coronary Artery Disease?

Coronary artery disease (CAD) occurs when the arteries that supply blood to the heart muscle (the coronary arteries) become hardened and narrowed. The arteries harden and narrow due to buildup of a material called plaque (plak) on their inner walls. The buildup of plaque is known as atherosclerosis (ATH-er-o-skler-O-sis). As the plaque increases in size, the insides of the coronary arteries get narrower and less blood can flow through them. Eventually, blood flow to the heart muscle is reduced, and, because blood carries much-needed oxygen, the heart muscle is not able to receive the amount of oxygen it needs. Reduced or cutoff blood flow and oxygen supply to the heart muscle can result in:

• Angina (AN-ji-na or an-JI-na). Angina is chest pain or discomfort that occurs when the heart does not get enough blood.
• Heart attack. A heart attack happens when a blood clot develops at the site of plaque in a coronary artery and suddenly cuts off most or all blood supply to that part of the heart muscle. Cells in the heart muscle begin to die if they do not receive enough oxygen-rich blood. This can cause permanent damage to the heart muscle.

• Heart failure. In heart failure, the heart can’t pump blood effectively to the rest of the body. Heart failure does not mean that the heart has stopped or is about to stop. Instead, it means that the heart is failing to pump blood the way that it should.
• Arrhythmias (a-RITH-me-as). Arrhythmias are changes in the normal beating rhythm of the heart. Some can be quite serious.

CAD is the most common type of heart disease. It is the leading cause of death in the United States in both men and women.

July 2006