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Understanding Coronary Artery Disease (CAD)

Front view of heart showing coronary arteries.To understand coronary artery disease (CAD), you need to know how your heart works. Your heart is a muscle that pumps blood throughout your body. To work right, your heart needs a steady supply of oxygen. It gets this oxygen from blood supplied by the coronary arteries.


Cross section of healthy artery.
Healthy Artery
Cross section of artery with damaged inner lining.
Damaged Artery
Cross section of artery with plaque buildup.
Narrowed Artery
Cross section of artery with plaque buildup and blood clot.
Blocked Artery

Healthy artery. When a coronary artery is healthy and has no blockages, blood flows through easily. Healthy arteries can easily supply the oxygen-rich blood your heart needs.

Damaged artery. Coronary artery disease begins when damage leads to the development of fatty streaks that progress into plaque (a fatty substance) building up within the artery wall. This damage could be caused by things like high blood pressure or smoking. This plaque buildup, called atherosclerosis, begins to narrow the arteries carrying blood to the heart.

Narrowed artery. As more plaque builds up, your artery has trouble supplying blood to your heart muscle when it needs it most, such as during exercise. You may not feel any symptoms when this happens. Or you may feel angina—pressure, tightness, achiness, or pain in your chest, jaw, neck, back, or arm.

Blocked artery. Plaque may tear, completely blocking the artery. Or a blood clot may plug the narrowed opening. When this happens, blood flow stops. Without oxygen-rich blood, part of the heart muscle becomes damaged and stops working. You may feel crushing pressure or pain in or around your chest. This is a heart attack (acute myocardial infarction, or AMI).

Online Medical Reviewer: Brown, Kim, APRN
Online Medical Reviewer: Image reviewed by StayWell medical illustration team.
Online Medical Reviewer: MMI board-certified, academically affiliated clinician
Date Last Reviewed: 2/19/2014
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