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National Heart, Lung, and Blood Institute
Heart Disease: 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
Reprinted September 1995