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Facts About Coronary Heart Disease
Some 7 million Americans suffer from coronary heart disease (CHD), the most common form of heart disease. This type of
heart disease is caused by a narrowing of the coronary arteries that feed the heart.
CHD is the number one killer of both men and women in the U.S. Each year, more than 500,000 Americans die of heart
attacks caused by CHD.
Many of these deaths could be prevented because CHD is related to certain aspects of lifestyle. Risk factors for CHD include
high blood pressure, high blood cholesterol, smoking, obesity, and physical inactivity--all of which can be controlled. Although
medical treatments for heart disease have come a long way, controlling risk factors remains the key to preventing illness and
death from CHD.
Who is at risk for CHD?
Risk factors are conditions that increase your risk of developing heart disease. Some can be changed and some cannot.
Although these factors each increase the risk of CHD, they do not describe all the causes of coronary heart disease; even with
none of these risk factors, you might still develop CHD.
- High blood pressure
- High blood cholesterol
- Physical inactivity
- Heredity (family history of CHD)
* Although stress may be a risk factor for CHD, scientists still do not know exactly how stress might be involved in heart
What is CHD?
Like any muscle, the heart needs a constant supply of oxygen and nutrients that are carried to it by the blood in the coronary
arteries. When the coronary arteries become narrowed or clogged and cannot supply enough blood to the heart, the result is
CHD. If not enough oxygen-carrying blood reaches the heart, the heart may respond with pain called angina. The pain is usually
felt in the chest or sometimes in the left arm and shoulder. (However, the same inadequate blood supply may cause no
symptoms, a condition called silent angina.)
When the blood supply is cut off completely, the result is a heart attack. The part of the heart that does not receive oxygen
begins to die, and some of the heart muscle may be permanently damaged.
What causes CHD?
CHD is caused by a thickening of the inside walls of the coronary
arteries. This thickening, called atherosclerosis, narrows the
space through which blood can flow, decreasing and sometimes
completely cutting off the supply of oxygen and nutrients to the
Atherosclerosis usually occurs when a person has high levels of
cholesterol, a fat-like substance, in the blood. Cholesterol and
fat, circulating in the blood, build up on the walls of the
arteries. The buildup narrows the arteries and can slow or
block the flow of blood. When the level of cholesterol in the
blood is high, there is a greater chance that it will be
deposited onto the artery walls. This process begins in most
people during childhood and the teenage years, and worsens as
they get older.
In addition to high blood cholesterol, high blood pressure and
smoking also contribute to CHD. On the average, each of these
doubles your chance of developing heart disease. Therefore, a
person who has all three risk factors is eight times more likely
to develop heart disease than someone who has none. Obesity and
physical inactivity are other factors that can lead to CHD.
Overweight increases the likelihood of developing high blood
cholesterol and high blood pressure, and physical inactivity
increases the risk of heart attack. Regular exercise, good
nutrition, and smoking cessation are key to controlling the risk
factors for CHD.
What are the symptoms of CHD?
Chest pain (angina) or shortness of breath may be the earliest
signs of CHD. A person may feel heaviness, tightness, pain,
burning, pressure, or squeezing, usually behind the breastbone
but sometimes also in the arms, neck, or jaws. These signs
usually bring the patient to a doctor for the first time.
Nevertheless, some people have heart attacks without ever having
any of these symptoms.
It is important to know that there is a wide range of severity
for CHD. Some people have no symptoms at all, some have mild
intermittent chest pain, and some have more pronounced and steady pain. Still
others have CHD that is severe enough to make normal everyday
Because CHD varies so much from one person to another, the way a
doctor diagnoses and treats CHD will also vary a lot. The
following descriptions are general guidelines to some tests and
treatments that may or may not be used, depending on the
Are there tests for CHD?
There is no one simple test--some or all of the following
procedures may be needed. These diagnostic procedures are used
to establish CHD, to determine its extent and severity, and to
rule out other possible causes of the symptoms.
After taking a careful medical history and doing a physical
examination, the doctor may use some tests to see how advanced
the CHD is. The only certain way to diagnose and assess the
extent of CHD is coronary angiography (see below); other tests
can indicate a problem but do not show exactly where it is.
An examination for CHD may include the following tests:
How is CHD treated?
- An electrocardiogram (ECG or EKG) is a graphic record of the
electrical activity of the heart as it contracts and rests.
Abnormal heartbeats and some areas of damage, inadequate blood
flow, and heart enlargement can be detected on the records.
- A stress test (also called a treadmill test or exercise ECG)
is used to record the heartbeat during exercise. This is done
because some heart problems only show up when the heart is
working hard. In the test, an ECG is done before, during,
and after exercising on a treadmill; breathing rate and blood
pressure may be measured as well. Exercise tests are useful
but are not completely reliable; false positives (showing a
problem where none exists) and false negatives (showing no
problem when something is wrong) are fairly common.
- Nuclear scanning is sometimes used to show damaged areas of
the heart and expose problems with the heart's pumping action.
A small amount of radioactive material is injected into a
vein, usually in the arm. A scanning camera records the
nuclear material that is taken up by heart muscle (healthy
areas) or not taken up (damaged areas).
- Coronary angiography (or arteriography) is a test used to
explore the coronary arteries. A fine tube (catheter) is put
into an artery of an arm or leg and passed through the tube
into the arteries of the heart. The heart and blood vessels
are then filmed while the heart pumps. The picture that is
seen, called an angiogram or arteriogram, will show problems
such as a blockage caused by atherosclerosis.
CHD is treated in a number of ways, depending on the seriousness
of the disease. For many people, CHD is managed with lifestyle
changes and medications. Others with severe CHD may need
surgery. In any case, once CHD develops, it requires lifelong
What kind of lifestyle changes can help a person with CHD?
Although great advances have been made in treating CHD, changing
one's habits remains the single most effective way to stop the
disease from progressing.
If you know that you have CHD, changing your diet to one low in
fat, especially saturated fat, and cholesterol will help reduce
high blood cholesterol, a primary cause of atherosclerosis. In
fact, it is even more important to keep your cholesterol low
after a heart attack to help lower your risk of having another
one. Eating less fat should also help you lose weight. If you
are overweight, losing weight can help lower blood cholesterol
and is the most effective lifestyle way to reduce high blood
pressure, another risk factor for atherosclerosis and heart
People with CHD can also benefit from exercise. Recent research
has shown that even moderate amounts of physical activity are
associated with lower death rates from CHD. However, people
with severe CHD may have to restrict their exercise somewhat. If
you have CHD, check with your doctor to find out what kinds of
exercise are best for you.
Smoking is one of the three major risk factors for CHD. Quitting
smoking dramatically lowers the risk of a heart attack and also
reduces the risk of a second heart attack in people who have
already had one.
What medications are used to treat coronary heart disease?
Medications are prescribed according to the nature of the
patient's CHD and other problems. The symptoms of angina can
generally be controlled by "beta-blocker" drugs that decrease the
workload on the heart, by nitroglycerine and other "nitrates" and
by "calcium-channel blockers" that relax the arteries, and by
other classes of drugs. The tendency to form clots is reduced by
aspirin or by other platelet inhibitory and anticoagulant drugs.
Beta-blockers are given to decrease the recurrence of heart
attack. For those with elevated blood cholesterol that is
unresponsive to dietary and weight loss measures,
cholesterol-lowering drugs may be prescribed, such as lovastatin,
colestipol, cholestyramine, gemfibrozil, and niacin. Impaired
pumping function of the heart may be treated with digitalis drugs
or ACE inhibitors. If there is high blood pressure or fluid
retention, these conditions are also treated.
Ask your doctor which medication you are taking, what it does,
and whether there are any side effects. Knowing more about this
will help you stick to the schedule that has been prescribed for
What types of surgery are used to treat CHD?
Many patients can control CHD with lifestyle changes and
medication. Surgery may be recommended for patients who continue
to have frequent or disabling angina despite the use of
medications, or people who are found to have severe blockages in
their coronary arteries.
Coronary angioplasty or balloon angioplasty begins with a
procedure similar to that described under angiography. However,
the catheter positioned in the narrowed coronary artery has a
tiny balloon at its tip. The balloon is inflated and deflated to
stretch or break open the narrowing and improve the passage for
blood flow. The balloon-tipped catheter is then removed.
Strictly speaking, angioplasty is not surgery. It is done while
the patient is awake and may last 1 to 2 hours. If angioplasty
does not widen the artery or if complications occur, bypass
surgery may be needed.
In a coronary artery bypass operation, a blood vessel, usually
taken from the leg or chest, is grafted onto the blocked artery,
bypassing the blocked area. If more than one artery is blocked,
a bypass can be done on each. The blood can then go around the
obstruction to supply the heart with enough blood to relieve
Bypass surgery relieves symptoms of heart disease but does not cure it. Usually
you will need to make a number of changes in your lifestyle after the operation.
If your normal lifestyle includes smoking, a high-fat diet, or no exercise,
changes are advised.
Several experimental catheter-surgical procedures for unblocking
coronary arteries are under study; their safety and effectiveness
have not yet been established. They include:
- Atherectomy, a procedure in which surgeons shave off thin
strips of the plaque blocking the artery and remove these
- Laser angioplasty; instead of using a balloon to open up the
blocked artery, doctors insert a catheter with a laser tip
that burns or breaks down the plaque.
- Insertion of a stent, a metal coil that can be permanently
implanted in a narrowed part of an artery to keep it propped
NIH Publication No. 93-2265
Revised July 1993
U.S. Department of Health and Human Services
Public Health Service
National Institutes of Health
National Heart, Lung, and Blood Institute