Like any other muscle, the heart needs oxygen to live and work. The coronary arteries branch from the aorta very close to the heart and carry oxygen-rich blood along the heart’s surface and into the muscle itself. There are three major coronary arteries: Right Coronary Artery (RCA), Left Anterior Descending Coronary Artery (LAD), and Circumflex Coronary Artery (Cx). Each of these three arteries branch into smaller arteries that supply every part of the heart muscle with blood.