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Facts About 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. 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 causes 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 than 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, thallium or
cardiolite 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. Also a stress echo may be used instead by the radioisotope test.
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. Aspirin may be used to help prevent
clotting of the blood.
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.
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