The blockage in your artery can be so severe that it can completely shut off the flow of blood to a part of your heart. For instance, a blood clot can block whatever small space remains in an artery that's been narrowed by plaque. If that happens, the result can be a heart attack. When you have a heart attack, the part of your heart muscle that doesn't get blood dies.
CHD can also cause sudden cardiac death, called SCD, which occurs when the heart suddenly stops working. This can be the result of a massive heart attack or a change in the heart rhythm, called an arrhythmia. Sudden cardiac death is also known as cardiac arrest, and it causes a quick and unexpected death.
To learn more about the possible complications of CHD, see What kinds of major health problems can my CHD cause? CHD is a serious condition, and it can be frightening to know you have it. But you can do something about it. The more you learn about CHD, what can be done about it, and especially what you can do yourself, the more control you can have over your own life.