Coronary
heart disease (CHD), or coronary artery disease, develops when the coronary
arteries become too narrow. The coronary arteries are the blood vessels that
supply oxygen and blood to the heart.
CHD tends to develop when cholesterol builds
up on the artery walls, creating plaques. These plaques cause the arteries to
narrow, reducing blood flow to the heart. A clot can sometimes obstruct the
blood flow, causing serious health problems.
Coronary arteries form the network of blood vessels on the
surface of the heart that feed it oxygen. If these arteries narrow, the heart
may not receive enough oxygen rich blood, especially during physical activity.
CHD can sometimes lead to heart attack.
It is the "most common type of heart disease in the United
States," where it accounts for more than 370,000 deaths every year.
Causes
CHD develops as a result of
injury or damage to the inner layer of a coronary artery. This damage causes
fatty deposits of plaque to build up at the injury site.
These deposits consist of cholesterol and other waste
products from cells. This buildup is called atherosclerosis.
If pieces of plaque break off or rupture, platelets will
cluster in the area in an attempt to repair the blood vessel. This cluster can
block the artery and reduce or block blood flow, which may lead to a heart
attack.
Below is a 3-D model of CHD, which is fully interactive.
Explore the model using your mouse pad or touchscreen to
understand more about CHD.
Symptoms
Symptoms
Angina may cause the following feelings across the chest:
- squeezing
- pressure
- heaviness
- tightening
- burning
- aching
Angina might also cause the following symptoms:
- indigestion
- heartburn
- weakness
- sweating
- nausea
- cramping
CHD can also lead to shortness of breath. If the heart and
other organs do not receive enough oxygen, any form of exertion can become very
tiring, which may cause a person to pant for air.
Complications
Heart attack occurs when the heart muscle does not have
enough blood or oxygen, such as when a blood clot develops from plaque in one
of the coronary arteries.
The formation of a blood clot is called coronary
thrombosis. This clot, if it is big enough, can stop the supply of blood to the
heart.
Symptoms of a heart attack include:
- chest
discomfort
- mild or
crushing chest pain
- coughing
- dizziness
- shortness
of breath
- a gray
pallor in the face
- general
discomfort
- panic
- nausea and
vomiting
- restlessness
- sweating
- clammy skin
The first symptom is usually chest pain that spreads to
the neck, jaw, ears, arms, and wrists, and possibly to the shoulder blades,
back, or abdomen.
Changing position, resting, or lying down is unlikely to
bring relief. The pain is often constant but may come and go. It can last from
a few minutes to several hours.
A heart attack is a medical emergency that can result in
death or permanent heart damage. If a person is showing symptoms of a heart
attack, it is vital to call the emergency services immediately.
Treatment
There is no cure for CHD. However, there are ways that a
person can manage the condition.
Treatment tends to involve making healthful lifestyle
changes, such as quitting
smoking, adopting a healthful diet, and getting regular exercise.
However, some people may need to take medications or
undergo medical procedures.
Medications
Medications that people can take
to reduce the risk or impact of CHD include:
- Beta-blockers:
A doctor may prescribe beta-blockers to
reduce blood
pressure and heart rate, especially among people who have
already had a heart attack.
- Nitroglycerin
patches, sprays, or tablets: These widen the arteries and reduce the
heart's demand for blood, as well as soothe chest pain.
- Angiotensin-converting
enzyme inhibitors: These bring down blood pressure and help slow or stop
the progression of CHD.
- Calcium channel
blockers: These will widen the coronary arteries, improving blood flow to
the heart and reducing hypertension.
- Statins:
These may have a positive impact on outcomes in CHD. One 2019 review found
that although taking statins cannot reduce the overall risk of death from
CHD, they can prevent development and reduce the risk of non-fatal heart
attacks. However, they might not be effective for people with cholesterol
disorders such as hyperlipidemia.
In the past, some people used aspirin to
lower their risk of CHD, but current guidelines only
recommend this for people with a high risk of heart attack, stroke,
angina, or other cardiovascular events. This is because aspirin is a blood
thinner, which increases a person's risk of bleeding.
Doctors now recommend focusing on lifestyle strategies,
such as adopting a healthful diet and getting regular moderate to intense
exercise. These strategies can reduce the risk of atherosclerosis.
Surgery
The following surgical procedures can open or replace
blocked arteries if they have become very narrow, or if symptoms are not
responding to medications:
- Laser
surgery: This involves making several very small holes in the heart
muscle. These encourage the formation of new blood vessels.
- Coronary
bypass surgery: A surgeon will use a blood vessel from another part of the
body to create a graft that bypasses the blocked artery. The graft may
come from the leg, for example, or an inner chest wall artery.
- Angioplasty
and stent placement: A surgeon will insert a catheter into the narrowed
part of the artery and pass a deflated balloon through the catheter to the
affected area. When they inflate the balloon, it compresses the fatty
deposits against the artery walls. They may leave a stent, or mesh tube,
in the artery to help keep it open.
On rare occasions, a person may need a heart transplant.
However, this is only if the heart has severe damage and treatment is not
working.
Prevention
Controlling blood cholesterol levels can help reduce a
person's risk of CHD. To better control blood cholesterol levels:
- be more
physically active
- limit
alcohol intake
- avoid
tobacco
- adopt a
diet with less sugar, salt, and saturated fats
People who already have CHD should ensure that they
control these factors by following the doctor's recommendations.
Risk factors
The following factors increase a person's risk of
developing CHD:
- having high
blood pressure, or hypertension
- having high
levels of low-density lipoprotein, or "bad," cholesterol
- having low
levels of high-density lipoprotein, or "good," cholesterol
- having a
diagnosis of diabetes,
in which the body cannot effectively remove sugar from the bloodstream
- having obesity
- smoking,
which increases inflammation and
increases cholesterol deposits in the coronary arteries
Some risk factors are not lifestyle-related. These may
include:
- having high
levels of the amino acid homocysteine, which
one 2015 study linked to a higher incidence of CHD - having high
levels of fibrinogen, a blood protein that encourages the clumping of
platelets to form blood clots
- having a
family history of CHD
- for women,
having been through menopause
- for men,
being over 45 years of age
Having high levels of lipoprotein(a) specifically is also
linked to a higher risk of cardiovascular disease and CHD.
Diagnosis
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A doctor can perform a physical
examination, take a thorough medical history, and order a number of tests to
diagnose CHD. For example:
- Electrocardiogram:
This records the electrical activity and rhythm of the heart.
- Holter
monitor: This is a portable device that a person wears under their clothes
for 2 days or more. It records all the electrical activity of the heart,
including the heartbeat.
- Echocardiogram:
This is an ultrasound
scan that monitors the pumping heart. It uses sound waves
to provide a video image.
- Stress test:
This may involve the use of a treadmill or medication that stresses the
heart in order to test how it functions when a person is active.
- Coronary
catheterization: A specialist will inject dye through a catheter they have
threaded through an artery, often in the leg or arm. The dye shows narrow
spots or blockages on an X-ray.
- CT scans:
These help the doctor visualize the arteries, detect calcium within fatty
deposits, and characterize any heart anomalies.
- Nuclear
ventriculography: This uses tracers, or radioactive materials, to create
an image of the heart chambers. A doctor will inject the tracers into the
vein. The tracers then attach to red blood cells and pass through the
heart. Special cameras or scanners trace the movement of the tracers.
- Blood
tests: Doctors can run these to measure blood cholesterol levels,
especially in people at risk of high blood cholesterol levels.
Summary
CHD develops when coronary arteries become too narrow. The
condition causes blockages in the arteries that feed oxygen-rich blood to the
heart.
CHD can be difficult to treat and may lead to a heart
attack or stroke. However, people can take steps to reduce their risk of CHD by
getting regular exercise, adopting a healthful diet, and avoiding or quitting
tobacco.
People should seek immediate medical attention if they
have chest pain and breathlessness, as this could indicate a heart attack.
Q:
Is CHD the most dangerous cardiovascular disease?
A:
CHD is the most dangerous cardiovascular disease, as it
causes the most deaths of any heart disease in the United States.
Having undetected or untreated high blood pressure or high
cholesterol can lead to a heart attack without causing any prior symptoms. Be
sure to see a doctor regularly and seek regular blood tests.
Even those who consider themselves to be healthy may have
high cholesterol and not know it.
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