What Is Coronary Artery Disease?

Coronary artery disease (CAD) — also called coronary heart disease or ischemic heart disease — is the most common type of heart disease and the leading cause of death in the United States. Approximately 20 million American adults have CAD, and it is responsible for more than 360,000 deaths annually. Understanding what coronary artery disease is, how it develops, and how it is detected and treated is foundational to understanding heart health.

WHAT ARE THE CORONARY ARTERIES?

The heart is a muscular pump that works continuously — beating approximately 100,000 times per day — and requires a constant supply of oxygenated blood to sustain its work. This blood is delivered by the coronary arteries: a network of vessels that arise from the aorta (the body's main artery) just above the aortic valve and course across the surface of the heart, branching into progressively smaller vessels that penetrate the heart muscle.

The major coronary arteries are:

• Left main coronary artery: Divides into two major vessels
• Left anterior descending (LAD) artery: Supplies the front and left side of the heart; often called the "widow maker" because blockage of the LAD is particularly dangerous
• Left circumflex artery (LCx): Supplies the left lateral and posterior heart wall
• Right coronary artery (RCA): Supplies the right ventricle and inferior (bottom) heart wall; in most people, also supplies the AV node (the electrical relay between the upper and lower chambers)