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.

Atherosclerosis means the fatty deposits that form under the inner lining of the blood vessels. When the coronary arteries become blocked, less blood can get through. The blockage can be small, or it may be large enough to fully obstruct blood flow. Blockage can occur in one or many coronary arteries.

Small blockages may not always affect the heart's performance. The person may not have symptoms until the heart needs more oxygen-rich blood than the arteries can supply. This commonly occurs during exercise or other activity. The pain that results is called stable angina.

If a blockage is large, angina pain can occur with little or no activity. This is known as unstable angina. In this case, the flow of blood to the heart is so limited that the person cannot do daily tasks without bringing on an angina attack. When the blood flow to an area of the heart is completely blocked, a heart attack occurs.

What are the signs and symptoms of the disease?

Symptoms of CHD vary widely and do not necessarily indicate the severity of the condition. The classic indicator of CHD is angina, or chest pain. The pain may radiate to the neck, jaw, or left arm. It is often described as a crushing, burning, or squeezing sensation. The person may also have shortness of breath.

Sometimes, a person may have no symptoms at all until he or she suffers a heart attack.

What are the causes and risks of the disease?

CHD affects people of all races. It can be caused by a combination of unhealthy lifestyle and genetics.

Coronary risk factors that increase the risk of CHD are as follows:

• cigarette smoking and secondhand smoke
• diabetes
• high blood cholesterol, especially a high level of LDL, the bad carrier for cholesterol ·
• high blood levels of triglycerides
• high blood pressure
• increasing age
• lack of exercise
• male gender
• overweight or obesity

Genetic factors that affect heart disease risk are beyond a person's control. These include a strong family history of the following:

• coronary heart disease
• heart attack
• high cholesterol

What can be done to prevent the disease?

Although family medical history or genetics can't be changed, a person can lower his or her risk for developing CHD. Here are some steps that a person can take to lower his or her coronary risk factors:

• Avoid smoking
• Control blood cholesterol and LDL
• Control diabetes
• Exercise regularly
• Follow a diet that is designed to lessen the risk factors for heart disease
• Keep high blood pressure under control