Heart Disease affects more than 20 million Americans, and is one of the leading causes of death in this country. But what exactly does the term heart disease mean? When most people talk about heart disease, they usually mean coronary artery disease, the illness which causes both angina and heart attacks. However, there are also other conditions that can affect our cardiovascular system, such as congestive heart failure and aneurysms. To better understand each of these diseases, it helps to review how the heart works. Basically the heart is a pump. Its purpose is to circulate blood to all of the organs of the body. The heart is made up of four chambers, two ventricles that pump blood out of the heart, and two atria, which hold the blood returning to the heart. The heart receives its entire supply of blood through the three coronary arteries. Coronary artery disease occurs when there is a buildup of fatty plaque known as atherosclerosis inside the coronary arteries. When the buildup is sufficient to restrict, but not stop, blood flow into the heart, the result is angina, a discomfort or pain in the chest. Angina isn't actually a disease, but rather is a symptom of coronary artery disease. When the buildup of atherosclerosis is sufficient to interrupt blood flow to the heart, the result is the death of heart muscle cells, commonly known as a heart attack. So, both angina and heart attacks are really caused by the buildup here, in the coronary arteries. Congestive Heart Failure, on the other hand occurs when the heart is pumping inefficiently and can no longer meet the body's need for blood. The ventricles, which are the main pumps within the heart, often are to blame for the insufficient blood flow. The "congestive" part of Congestive Heart Failure comes from the backup of blood in the veins leading into the heart. This backup causes the kidney to retain fluids. Other, less common diseases affect other parts of the heart. For example, when a patient is suffering from an aneurysm, that means that their aorta has swollen, creating a bulge in the artery. Understanding heart disease is an important first step towards prevention. It may also be worthwhile to learn how high blood pressure and cholesterol can impact your heart health, and to incorporate some of the lifestyle tips on preventing heart disease available in other videos in this library. Remember, heart disease is both complex and serious, and you should always consult a physician if you are concerned about your cardio health. If you are interested in learning more about this topic, check out other videos and sources on this subject.