By Eric Berlin, MD
Coronary heart disease, or CHD, refers to the narrowing of the coronary arteries that supply blood to the heart. CHD is a progressive disease that increases the risk of heart attack and sudden death.

What is going on in the body?

In order for the heart to pump as it should, the heart muscle needs a steady supply of oxygen-rich blood. This blood is delivered by the coronary arteries. Two main vessels branch out to supply blood to the entire muscle of the heart. The heart needs more oxygen during exercise and high levels of activity. Less is needed when the person is at rest.