Coronary arteries of the heart. Coloured arterio- gram (X-ray) of the healthy heart showing its two coronary arteries. The heart is outlined in yellow, with the coronary artery blood supply (red) seen on it's surface. There are two large coronary arteries: the right coronary artery (at left); the left coronary artery (at right). These branching blood vessels supply the heart muscle with the oxygen it needs in order to continue pumping. Blockages or disease of these arteries may result in heart attack. Arteriography is the X-ray examination of an artery in which the blood has been injected with an X-ray opaque dye. The technique is used to detect artery disease.