The coronary arteries are the blood vessels that supply oxygenated blood to the heart muscle (myocardium) itself. Despite being the body’s most powerful pump, the heart cannot use the blood flowing through its chambers directly; it relies on its own dedicated arterial supply. There are two main coronary arteries, both arising from the base of the aorta just above the aortic valve.
The left coronary artery (LCA) divides shortly after its origin into the left anterior descending (LAD) artery, which runs down the front of the heart and supplies the main pumping wall of the left ventricle, and the left circumflex (LCx) artery, which wraps around the left side of the heart. The right coronary artery (RCA) runs along the right side of the heart and supplies the right ventricle and, in most people, the inferior wall of the left ventricle and the electrical conduction system including the SA node and AV node.
The coronary arteries branch progressively into smaller vessels that penetrate the heart muscle. Blood flow through them occurs primarily during diastole (when the heart is relaxed between beats), because the contracting heart muscle compresses the vessels during systole.
Blockage or narrowing of a coronary artery by atherosclerotic plaque reduces blood flow to the supplied area of heart muscle, causing angina or, if complete blockage occurs suddenly, a heart attack. A heart attack affecting a large area of myocardium can trigger ventricular fibrillation and cardiac arrest. See also: Coronary Angiography, Percutaneous Coronary Intervention.
« Back to Glossary Index