Complications of coronary artery disease
How does coronary artery disease affect my heart?
Coronary artery disease (CAD) can affect your heart in four ways.
CAD and heart attacks
If one of your coronary arteries becomes blocked, part of your heart muscle will be deprived of blood. Without blood, your heart muscle does not get any oxygen. If a portion of your heart muscle goes without oxygen for long enough, it will die. This is a heart attack.
The medical name for a heart attack is a myocardial infarction (MI). "Myocardial" means having to do with your heart muscle, and "infarction" refers to the permanent damage to your heart. An MI usually happens because you have atherosclerosis in your coronary arteries, which means that a plaque has built up and narrowed the inside of your arteries.
If the plaque ruptures, a blood clot can form in your coronary artery, just as your blood clots when you cut your finger. This clot can abruptly block your artery and cut off the flow of blood to your heart muscle. If part of your heart muscle dies, that part stops working and becomes scar tissue. The rest of your heart may continue to function normally, but it may not function as well as it did before the heart attack.
CAD and ischemia
CAD can deprive your heart muscle of oxygen without causing a heart attack. CAD can still affect your heart's ability to function even if your heart muscle has not been permanently damaged by a heart attack. If the atherosclerosis in your arteries is severe enough, it can restrict the flow of blood and oxygen to certain areas of your heart.
This lack of oxygen, called ischemia, may come and go or may affect your heart continuously. When you have ischemia, your heart muscle may get just enough oxygen to stay alive but not enough oxygen to work normally. If your heart can't function normally from this lack of oxygen, you may develop heart failure.
CAD and abnormal heartbeats (arrhythmia)
In addition, ischemia can short-circuit the heart's electrical system, which controls your heart's rhythm. When this happens, you may develop an abnormal heartbeat (arrhythmia). Your heartbeat—or more accurately, heart rhythm—refers to the way the four heart chambers all pump in a synchronized, orderly fashion. The heart has its own electrical system that controls heart rhythm. A problem with this electrical system can upset your heart's rhythm, a condition called arrhythmia.
An arrhythmia can mean that your heart does not beat at a consistent rate or that your heart is beating too fast or two slow. Ischemia or a heart attack can cause an abnormality in your heart's electrical system through structural damage to your heart muscle or through a change in the chemical signaling system.
CAD and heart valve problems
When CAD prevents adequate oxygen from reaching the heart (ischemia), it can result in a condition known as mitral valve regurgitation, or leakiness of the mitral valve.
The mitral valve regulates the flow of blood between the left atrium and the left ventricle, the two chambers on the left side of your heart
. The job of the mitral valve is to allow blood to flow from your left atrium to the left ventricle but prevent blood from flowing backward. Mitral valve regurgitation means that blood is leaking back into your left atrium. Mitral valve regurgitation can weaken your heart muscle and cause heart failure, among other problems.
CAD can cause mitral valve regurgitation in several ways. Two common causes of mitral valve regurgitation are described below.
- The mitral valve is attached to the left ventricle by a specialized section of heart muscle called the papillary muscles. These muscles help the valve to function normally. If CAD clogs the blood vessels that supply oxygen to these muscles, ischemia or heart attack will occur and prevent the muscles from working normally. As a result, the mitral valve may leak.
- If a large heart attack occurs, the left ventricle may start to enlarge (dilate). This causes the valve to leak because it cannot close completely.
| Author: | Robin Parks, MS | Last Updated: January 8, 2008 |
| Medical Review: | Caroline S. Rhoads, MD - Internal Medicine Robert A. Kloner, MD, PhD - Cardiology Ruth Schneider, MPH, RD - Diet and Nutrition | |
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