Facts About Angina
What is angina?
ANGINA PECTORIS ("ANGINA")
IS A recurring pain or discomfort in the chest that happens
when some part of the heart does not receive enough blood. It
is a common symptom of coronary heart disease (CHD), which occurs
when vessels that carry blood to the heart become narrowed and
blocked due to atherosclerosis
Angina feels like
a pressing or squeezing pain, usually in the chest under the
breast bone, but sometimes in the shoulders, arms, neck, jaws,
or back. Angina is usually precipitated by exertion. It is usually
relieved within a few minutes by resting or by taking prescribed
angina medicine.
What brings
on angina?
Episodes of angina
occur when the heart's need for oxygen increases beyond the
oxygen available from the blood nourishing the heart. Physical
exertion is the most common trigger for angina. Other triggers
can be emotional stress, extreme cold or heat, heavy meals,
alcohol, and cigarette smoking.
Does angina
mean a heart attack is about to happen?
An episode of angina
is not a heart attack. Angina pain means that some of the heart
muscle in not getting enough blood temporarily--for example,
during exercise, when the heart has to work harder. The pain
does NOT mean that the heart muscle is suffering irreversible,
permanent damage. Episodes of angina seldom cause permanent
damage to heart muscle.
In contrast, a heart
attack occurs when the blood flow to a part of the heart is
suddenly and permanently cut off. This causes permanent damage
to the heart muscle. Typically, the chest pain is more severe,
lasts longer, and does not go away with rest or with medicine
that was previously effective. It may be accompanied by indigestion,
nausea, weakness, and sweating. However, the symptoms of a heart
attack are varied and may be considerably milder.
When someone has
a repeating but stable pattern of angina, an episode of angina
does not mean that a heart attack is about to happen. Angina
means that there is underlying coronary heart disease. Patients
with angina are at an increased risk of heart attack compared
with those who have no symptoms of cardiovascular disease, but
the episode of angina is not a signal that a heart attack is
about to happen. In contrast, when the pattern of angina changes--if
episodes become more frequent, last longer, or occur without
exercise--the risk of heart attack in subsequent days or weeks
is much higher.
A person who has
angina should learn the pattern of his or her angina--what cause
an angina attack, what it feels like, how long episodes usually
last, and whether medication relieves the attack. If the pattern
changes sharply or if the symptoms are those of a heart attack,
one should get medical help immediately, perhaps best done by
seeking an evaluation at a nearby hospital emergency room.
Is all chest
pain "angina?"
No, not at all. Not
all chest pain is from the heart, and not all pain from the
heart is angina. For example, if the pain lasts for less that
30 seconds or if it goes away during a deep breath, after drinking
a glass of water, or by changing position, it almost certainly
is NOT angina and should not cause concern. But prolonged pain,
unrelieved by rest and accompanied by other symptoms may signal
a heart attack.
How is angina
diagnosed?
Usually the doctor
can diagnose angina by noting the symptoms and how they arise.
However one or more diagnostic tests may be needed to exclude
angina or to establish the severity of the underlying coronary
disease. These include the electrocardiogram (ECG) at rest,
the stress test, and x- rays of the coronary arteries (coronary
"arteriogram" or "angiogram").
The ECG records electrical
impulses of the heart. These may indicate that the heart muscle
is not getting as much oxygen as it needs ("ischemia"); they
may also indicate abnormalities in heart rhythm or some of the
other possible abnormal features of the heart. To record the
ECG, a technician positions a number of small contacts on the
patient's arms, legs, and across the chest to connect them to
an ECG machine.
For many patients
with angina, the ECG at rest is normal. This is not surprising
because the symptoms of angina occur during stress. Therefore,
the functioning of the heart may be tested under stress, typically
exercise. In the simplest stress test, the ECG is taken before,
during, and after exercise to look for stress related abnormalities.
Blood pressure is also measured during the stress test and symptoms
are noted.
A more complex stress
test involves picturing the blood flow pattern in the heart
muscle during peak exercise and after rest. A tiny amount of
a radioisotope, usually thallium, is injected into a vein at
peak exercise and is taken up by normal heart muscle. A radioactivity
detector and computer record the pattern of radioactivity distribution
to various parts of the heart muscle. Regional differences in
radioisotope concentration and in the rates at which the radioisotopes
disappear are measures of unequal blood flow due to coronary
artery narrowing, or due to failure of uptake in scarred heart
muscle.
The most accurate
way to assess the presence and severity of coronary disease
is a coronary angiogram, an x-ray of the coronary artery. A
long thin flexible tube (a "catheter") is threaded into an artery
in the groin or forearm and advanced through the arterial system
into one of the two major coronary arteries. A fluid that blocks
x-rays (a "contrast medium" or "dye") is injected. X-rays of
its distribution show the coronary arteries and their narrowing.
How is angina
treated?
The underlying coronary
artery disease that causes angina should be attacked by controlling
existing "risk factors." These include high blood pressure,
cigarette smoking, high blood cholesterol levels, and excess
weight. If the doctor has prescribed a drug to lower blood pressure,
it should be taken as directed. Advice is available on how to
eat to control weight, blood cholesterol levels, and blood pressure.
A physician can also help patients to stop smoking. Taking these
steps reduces the likelihood that coronary artery disease will
lead to a heart attack.
Most people with
angina learn to adjust their lives to minimize episodes of angina,
by taking sensible precautions and using medications if necessary.
Usually the first
line of defense involves changing one's living habits to avoid
bringing on attacks of angina. Controlling physical activity,
adopting good eating habits, moderating alcohol consumption,
and not smoking are some of the precautions that can help patients
live more comfortably and with less angina. For example, if
angina comes on with strenuous exercise, exercise a little less
strenuously, but do exercise. If angina occurs after heavy meals,
avoid large meals and rich foods that leave one feeling stuffed.
Controlling weight, reducing the amount of fat in the diet,
and avoiding emotional upsets may also help.
Angina is often controlled
by drugs. The most commonly prescribed drug for angina is nitroglycerin,
which relieves pain by widening blood vessels. This allows more
blood to flow to the heart muscle and also decreases the work
load of the heart. Nitroglycerin is taken when discomfort occurs
or is expected. Doctors frequently prescribe other drugs, to
be taken regularly, that reduce the heart's workload. Beta blockers
slow the heart rate and lessen the force of the heart muscle
contraction. Calcium channel blockers are also effective in
reducing the frequency and severity of angina attacks.
What if medication
fails to control angina?
Doctors may recommend
surgery or angioplasty if drugs fail to ease angina or if the
risk of heart attack is high. Coronary artery bypass surgery
is an operation in which a blood vessel is grafted onto the
blocked artery to bypass the blocked or diseased section so
that blood can get to the heart muscle. An artery from inside
the chest (an "internal mammary" graft) or long vein from the
leg (a "saphenous vein" graft) may be used.
Balloon angioplasty
involves inserting a catheter with a tiny balloon at the end
into a forearm or groin artery. The balloon is inflated briefly
to open the vessel in places where the artery is narrowed. Other
catheter techniques are also being developed for opening narrowed
coronary arteries, including laser and mechanical devices applied
by means of catheters.
Can a person
with angina exercise?
Yes. It is important
to work with the doctor to develop an exercise plan. Exercise
may increase the level of pain-free activity, relieve stress,
improve the heart's blood supply, and help control weight. A
person with angina should start an exercise program only with
the doctor's advice. Many doctors tell angina patients to gradually
build up their fitness level--for example, start with a 5-minute
walk and increase over weeks or months to 30 minutes or 1 hour.
The idea is to gradually increase stamina by working at a steady
pace, but avoiding sudden bursts of effort.
What is the
difference between "stable" and "unstable" angina?
It is important to
distinguish between the typical stable pattern of angina and
"unstable" angina.
Angina pectoris often
recurs in a regular or characteristic pattern. Commonly a person
recognizes that he or she is having angina only after several
episodes have occurred, and a pattern has evolved. The level
of activity or stress that provokes the angina is somewhat predictable,
and the pattern changes only slowly. This is "stable" angina,
the most common variety.
Instead of appearing
gradually, angina may first appear as a very severe episode
or as frequently recurring bouts of angina. Or, an established
stable pattern of angina may change sharply; it may by provoked
by far less exercise than in the past, or it may appear at rest.
Angina in these forms is referred to as "unstable angina" and
needs prompt medical attention.
The term "unstable
angina" is also used when symptoms suggest a heart attack but
hospital tests do not support that diagnosis. For example, a
patient may have typical but prolonged chest pain and poor response
to rest and medication, but there is no evidence of heart muscle
damage either on the electrocardiogram or in blood enzyme tests.
Are there
other types of angina?
There are two other
forms of angina pectoris. One, long recognized but quite rare,
is called Prinzmetal's or variant angina. This type is caused
by vasospasm, a spasm that narrows the coronary artery and lessens
the flow of blood to the heart. The other is a recently discovered
type of angina called microvascular angina. Patients with this
condition experience chest pain but have no apparent coronary
artery blockages. Doctors have found that the pain results from
poor function of tiny blood vessels nourishing the heart as
well as the arms and legs. Microvascular angina can be treated
with some of the same medications used for angina pectoris.
Additional
Resources:
Facts About Blood
Cholesterol (revised 1994), NIH Publication No. 94-2696
Fact About Coronary
Heart Disease (reprinted 1993), NIH Publication No. 93-2265
Facts About Heart
Failure (reprinted 1995) NIH Publication No. 95-923
Facts About Heart
Disease and Women: So You Have Heart Disease, NIH Publication
No. 95-2645
High Blood Pressure
and What You Can Do About It, No. 55-222A
So You Have High
Blood Cholesterol (revised 1993), NIH Publication No. 93-2922
Step by Step: Eating
to Lower Your High Blood Cholesterol (revised 1994) NIH Publication
No. 94-2920
For Further
Information
Call or
Write:
National
Heart, Lung, and Blood Institute
Information Office
P.O. Box 30105
Bethesda, MD 20892-0105
Telephone: (301) 592-8573
U.S. DEPARTMENT OF HEALTH AND
HUMAN SERVICES
Public Health Service
National Institutes of Health
National Heart, Lung, and Blood Institute
NIH Publication
No. 95-2890
September 1995
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