"275 Figure 4 . Plaque Buildup When damage occurs, your body starts a healing process. The healing may cause plaque to build up where the arteries are damaged. Plaque is made up of deposits of cholesterol and other substances in the artery. This progression of plaque build up is called atherosclerosis . The buildup of plaque in the coronary arteries may start in childhood. Over time, plaque can narrow or block some of your coronary arteries. This reduces the flow of oxygen - rich blood to your heart muscle. Eventually, an area of plaque can rupture (break open). If this happens, blood cell fragments called platelets will stick to the site of the injury and may clump together to form blood clots. Blood clots narrow the coronary arteries even more and worsen angina (chest discomfort or pain ) or cause a heart attack. Over time, CAD can weaken the heart muscle. This may lead to heart failure, a serious condition where the heart can’t pump blood the way that it should. An irregular heartbeat, or arrhythmia, also can develop. Other Conditions R elated to Heart Disease Coronary artery disease is the most common type of heart disease, but there are many other conditions that affect the heart: • Acute coronary syndrome is a term that includes heart attack and unstable angina. • Angina, a symptom of coro nary artery disease, is chest pain or discomfort that occurs when the heart muscle is not getting enough blood. Angina may feel like pressure or a squeezing pain in the chest. The pain also may occur in the shoulders, arms, neck, jaw, or back. It may feel like indigestion. There are two forms of angina — stable or unstable: o Stable angina happens during physical activity or under mental or emotional stress. o Unstable angina is chest pain that occurs even while at rest, without apparent reason. This type of angi na is a medical emergency. • Aortic aneurysm and dissection are conditions that can affect the aorta, the major artery that carries blood from the heart to the body. An aneurysm is an enlargement in the aorta that can rupture or burst. A dissection is a tear in the aorta. Both of these conditions are medical emergencies. • Arrhythmias are irregular or unusually fast or slow heartbeats. Arrhythmias can be serious. One example is called ventricular fibrillation. This type of arrhythmia causes an abnormal heart rhythm that leads to death unless treated right away with an electrical shock to the heart (called defibrillation). Other arrhythmias are less severe"