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Heart Disease 101

        Health | Heart

Introduction to How Heart Disease Works
blocked artery
HowStuffWorks.com
Heart disease is the leading cause of death in the United States. Learn about heart disease, risk factors for heart disease, angina and heart attacks.

Heart disease is the leading cause of death in the U.S. At some point in your life, either you or one of your loved ones will be forced to make decisions about some aspect of heart disease. Knowing something about the anatomy and functioning of the heart, in particular how angina and heart attacks work, will enable you to make informed decisions about your health.

Heart disease can strike suddenly and require you to make decisions quickly. Being informed prior to an emergency is a valuable asset to you and your family.

In this article we will discuss various heart diseases and how they can lead to a heart attack, or even a stroke. We will also look at how heart attacks are treated and what you should do to prevent heart disease.

The basics Coronary Artery Disease (CAD), Coronary Heart Disease (CHD), Ischemic Heart Disease (IHD) and Arteriosclerotic Cardiovascular Disease (ASCVD) are all different names for the same disease. This disease is caused by atherosclerosis, which is a buildup of fatty deposits (atheroma) in the coronary arteries. See the figure below:

Coronary arteries supply blood to the heart muscle. When a blockage occurs in one of these arteries, blood flow to the heart muscle is decreased. This becomes most evident during exertion. During exertion, the heart muscle is working harder and needs more oxygen-enriched blood than usual. By preventing the much needed increase in blood flow, the blockage deprives the heart muscle of oxygen thereby causing the heart muscle to hurt. This chest pain is called angina or Angina Pectoris. When the heart muscle goes without sufficient oxygen, the muscle is said to be ischemic. If cell death occurs it is called infarction. Since a heart attack is cell death of heart muscle (myocardium), it is called a Myocardial Infarction (MI). The condition that causes CAD, angina and heart attacks is called atherosclerosis.

Arteriosclerosis is a more general term for hardening of the arteries. Atherosclerosis is a type of arteriosclerosis that causes a buildup of fatty material (referred to as atheromas and plaques) along the inner lining of arteries. Depending on where these blockages occur, they can cause a number of different outcomes:

  • If the blockage occurs in a coronary artery, it causes chest pain (angina).
  • If the blockage is complete, it can cause a heart attack (Myocardial Infarction or MI).
  • If the blockage occurs in one of the arteries near the brain, a stroke can occur.
  • If a blockage occurs in a leg artery, it causes Peripheral Vascular Disease (PVD) and can cause pain while walking called intermittent claudication.
Up Next

­Atherosclerosis takes many years, even decades to develop and the condition can easily go unnoticed. Sometimes symptoms such as angina will gradually indicate the condition. However, it can also become evident in a sudden and severe way, in the form of a heart attack.

Let's take a look at some of the risk factors for atherosclerosis. Some of these factors are things you can control. By being proactive, you could reduce your risk.