Coronary arteries supply blood to the heart muscle, The left one, arises from the aorta and feeds blood to the left side of the heart and the right one supplies blood to the right ventricle, the right atrium, and the SA (sinoatrial) and AV (atrioventricular) nodes, which regulate the heart rhythm. Blockage in this vessel result in reducing the flow of oxygen and nutrients to the heart muscle and that can lead to a heart attack. Atherosclerosis and arteriosclerosis are the most common causes of heart disease.