Heart disease is caused by narrowing of the coronary arteries that feed the heart. Like any muscle, the heart needs a constant supply of oxygen and nutrients, which are carried to it by the blood in the coronary arteries. When the coronary arteries become narrowed or clogged by cholesterol and fat deposits--a process called atherosclerosis--and cannot supply enough blood to the heart, the result is coronary heart disease (CHD). If not enough oxygen-carrying blood reaches the heart, you may experience chest pain called angina. If the blood supply to a portion of the heart is completely cut off by total blockage of a coronary artery, the result is a heart attack. This is usually due to a sudden closure from a blood clot forming on top of a previous narrowing.

Cholesterol is a waxy, fat-like substance that occurs naturally in all parts of the body and that your body needs to function normally. It is present in cell walls or membranes everywhere in the body, including the brain, nerves, muscle, skin, liver, intestines, and heart. Your body uses cholesterol to produce many hormones, vitamin D, and the bile acids that help to digest fat. It takes only a small amount of cholesterol in the blood to meet these needs. If you have too much cholesterol in your bloodstream, the excess is deposited in arteries, including the coronary arteries, where it contributes to the narrowing and blockages that cause the signs and symptoms of heart disease.

The Framingham Heart Study established that high blood cholesterol is a risk factor for coronary heart disease (CHD). Results of the Framingham study showed that the higher the cholesterol level, the greater the CHD risk. On the other end of the spectrum, CHD is uncommon at total cholesterol levels below 150 milligrams per deciliter (mg/dL). A direct link between high blood cholesterol and CHD has been confirmed by the Lipid Research Clinics-Coronary Primary Prevention Trial (1984) which showed that lowering total and LDL ("bad") cholesterol levels significantly reduces CHD. A series of more recent trials of cholesterol lowering using statin drugs have demonstrated conclusively that lowering total cholesterol and LDL-cholesterol reduces the chance of having a heart attack, needing bypass surgery or angioplasty, and dying of CHD-related causes.

Medications may be needed in addition to making lifestyle changes. Some medications decrease the workload on your heart and relieve your symptoms. Others decrease your chance of having a heart attack or sudden death, and prevent or delay the need for a special procedure (angioplasty or bypass surgery). Some common medications used to treat CAD are:

Cholesterol-lowering medications.

Anticoagulants (an-ty-ko-AG-u-lants) prevent clots from forming in your arteries and blocking blood flow.

Aspirin, an antiplatelet medication to prevent clots from forming in your arteries and blocking blood flow. Aspirin may not be appropriate for some people because it increases the risk of bleeding. Discuss the benefits and risk with your doctor before starting aspirin therapy.

Other antiplatelet (an-ty-PLAYT-lit) medications stop platelets from clumping together to form clots. These medications may be given to people who have had a heart attack, have angina, or who experience angina after angioplasty.

ACE inhibitors lower blood pressure and reduce the strain on your heart. They also may reduce the risk for a future heart attack and heart failure.

Beta-blockers slow your heart rate and lower your blood pressure to decrease the workload on your heart. Beta-blockers are used to relieve angina and may also reduce the risk of a future heart attack.

Calcium channel blockers relax blood vessels and lower your blood pressure. These medications can reduce your heart's workload, help coronary arteries open, and relieve and control angina.

Nitroglycerin to prevent or relieve chest pain.

Long-acting nitrates open up the arteries to the heart, increasing blood flow to the heart muscle and relieving chest pain. Long-acting nitrates can limit the occurrence of chest pain when used regularly over a long period.

Glycoprotein IIb-IIIa inhibitors are very strong antiplatelet medications that are used in the hospital during and after angioplasty or to treat angina.

Thrombolytics dissolve the clots that can occur during heart attacks. You need to get to the hospital as soon as possible if you think you are having a heart attack to get thrombolytic therapy.