Overview, Causes, & Risk Factors
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 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
high blood cholesterol, especially a high level of LDL, the bad carrier for cholesterol
high blood levels of triglycerides
high blood pressure
lack of exercise
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
Symptoms & Signs
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.
Diagnosis & Tests
How is the disease diagnosed?
The diagnosis of CHD starts with a medical history and physical exam. An electrocardiogram, or
EKG, may show abnormalities. However, an EKG may be normal
between attacks of angina.
A stress EKG is an EKG taken before, during,
and after exercise. It is designed to bring on an attack of angina and record
the changes that take place in the heart. Sometimes the person is
injected with a substance called thallium during the stress test. Special
pictures are then taken of the heart. The thallium scan can show areas of the
heart that are damaged.
The most reliable test for diagnosing CHD is a cardiac catheterization. In this procedure,
a thin hollow tube or catheter is placed into an artery in the leg or arm. It
is then passed through the artery and into the coronary artery. A contrast
agent is injected into the tube. This allows the doctor to watch the blood flow through
the heart and its arteries.
Other techniques that are being used to help in the diagnosis of CHD include
stress echocardiograms and new generations of CT scans.
Prevention & Expectations
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:
Control blood cholesterol and LDL.
Follow a diet that is designed to lessen the risk factors for
Keep high blood pressure under control.
Before menopause, women have some protection against heart disease. Experts believe
this is due in part to the fact that they have adequate levels of estrogen in their bodies. This hormone may have a protective effect. Estrogen tends to raise HDL cholesterol, known as the
good cholesterol. It also lowers total cholesterol. There is no proof that estrogen replacement therapy has this same protective effect in a woman who has gone through menopause. Estrogen replacement therapy is a form of hormone replacement therapy, or HRT.
In fact, the latest recommendation from the American Heart Association, or AHA, does not advise starting HRT for the sole purpose of preventing heart disease. There is not enough data to support this. This same advisory issued by the AHA in 2001 recommends that women who already have heart disease should not be started on HRT. In fact, a recent study has even shown that if HRT is started after a woman has a heart attack, she may be at a higher risk for worsening of her angina, or having other serious cardiac complications.
What are the long-term effects of the disease?
CHD is a progressive disease that can lead to heart attack and sudden death.
What are the risks to others?
Coronary heart disease is not contagious. However, it does tend to run in families.
Treatment & Monitoring
What are the treatments for the disease?
Several types of medicines are often used together to reduce the
symptoms of stable angina caused by CHD.
Beta-blockers, such as atenolol or metoprolol, are used to decrease
the work level of the heart.
Nitrates, such as nitroglycerin or isosorbide mononitrate, help to
expand the blood vessels that supply the heart.
Aspirin may prevent heart attacks and warfarin may prevent blood clots.
However, the use of warfarin in treating stable angina remains controversial.
Calcium channel blockers, such as diltiazem, nifedipine, or verapamil, have been used for more than 20
years to open the coronary arteries and lower high blood pressure. However,
two recent studies have found that people who take a calcium channel blocker
have a much higher incidence of complications than people taking other
medicines for high blood pressure. One study, for example, found that the
risk of heart attack was 27% greater,
and the risk of congestive heart
failure was 26% higher. The American Heart Association recommends that
people discuss risks and benefits of the medicine with the healthcare
Several surgical procedures can be used to reduce the symptoms of stable angina
from coronary artery disease, such as:
angioplasty, a procedure in which a tube with a balloon is inserted to reopen the artery
atherectomy, which involves removing plaques that cause narrowing of a
laser surgery, which uses light
waves to dissolve plaques
placement of a stent, a rigid tube, into the artery
at the reopened area to keep it from narrowing again
What are the side effects of the treatments?
Side effects vary depending on the treatment used:
Aspirin and warfarin increase the risk of bleeding.
Beta-blockers can cause a slow
heartbeat, low blood pressure,
depression, erectile dysfunction, and unpleasant dreams.
Calcium channel blockers can cause flushing, nausea, headache, swelling of
the ankles, low blood pressure, and
weakness. These medicines have
recently been linked with a higher risk of heart attack and congestive
Nitrates can cause headaches and
low blood pressure.
Surgery can result in infection, bleeding, allergic reaction to
anesthesia, and even death.
What happens after treatment for the disease?
Most people who have coronary heart disease are advised to start a regular
exercise program. A person who has CHD should make every effort to reduce coronary risk factors. This may include
smoking cessation, control of other
diseases such as diabetes and high blood pressure, and following a healthy
diet for heart disease. Medicines
may need to be adjusted to get the best response.
How is the disease monitored?
The person will have regular examinations and tests by the healthcare provider
to check the progress of the coronary heart disease. Any new or worsening
symptoms should be reported to the healthcare provider.