Angina |
Coronary Artery Disease Medical Treatment of Angina Heart Attack |
Angina (pronounced an-ji-na) or angina pectoris is produced when the supply
of oxygen that is carried by blood is unable to meet the demands of the heart
muscle. The decreased supply of blood is created by an obstruction within the
coronary artery which impedes blood flow across it. Atherosclerosis is the
commonest cause of obstruction. However, obstruction may also result from
coronary artery spasm or the use of "crack" cocaine. Angina pectoris is a
recurring symptom and usually occurs in the form of chest discomfort (tightness,
fullness, squeezing, heaviness, burning or pain) in the center of the chest and
/or over the left breast). The discomfort may move to the left shoulder and arm
(although it may move to both shoulders/arms, throat, jaw, or even the lower
portion of the chest or upper abdomen). It may be accompanied by shortness of
breath, sweating, weakness, dizziness or nausea, or numbness in the shoulders,
arms and hands. When the build up of plaque is gradual, the patient's symptoms
are relatively predictable and stable. Such patient's usually have symptoms that
are provoked by specific levels of exercise. They are generally brief, last only
2-3 minutes, and subside promptly with cessation of exercise or following the
use of a nitroglycerin tablet. This pattern of pain is known as stable angina.
The partial and temporary decrease in oxygen supply to the heart muscle does not
generally cause permanent damage (unlike a heart attack).
Some patients may have atypical (not typical) symptoms. For example, the pain
may be confined to left shoulder, throat, jaw, or between the shoulder blades.
Others may have shortness of breath or sudden weakness, while approximately 10%
may have no symptoms, even when the heart is severely stressed or undergoing a
heart attack. Such patients are said to have a defective warning system.
Diabetic patients are more prone to have atypical or no symptoms.
Because there are several causes of chest pain that are unrelated to the
heart, many patients tend to ignore their symptoms attributing it to heartburn,
mitral valve prolapse, a gall bladder attack, muscle sprain, etc. If you have
risk factors for coronary artery disease and are having unusual symptoms
suggestive of angina or a heart attack, make sure that you consult your doctor
about your complaints.
The following section will walk you through the various phases of
atherosclerosis. The following "lecture" describes various phases of the
disease. The pictures will change automatically during the audio presentation.
You can play, stop, and rewind the animation/narration by clicking on the
buttons below.
Atherosclerosis begins with the deposition of fatty streaks on the inner
lining of the artery. Additional deposits lead to a bulky atheroma that begins
to encroach into the channel of the coronary artery. Fibers begin to grow into
the atheroma causing harder plaques. The plaque of atherosclerosis may develop a
crack on its surface. This is known as plaque rupture which can result in the
deposit of a blood clot at the site of the blockage. If the blood clot totally
blocks flow to the heart muscle, a heart attack usually results.
However, if the clot causes a partial blockage, the patient may develop
unstable angina. Such patients have prolonged, frequent and more severe episodes
of angina. The discomfort may be the patient's first symptom (in which case it
is called new onset angina). In other cases, stable angina gradually or suddenly
changes into a pattern of unstable angina.
The chest discomfort of unstable angina may become more frequent, last
longer, be more intense, be brought on by lesser degrees of exertion (compared
to prior symptoms), appear at rest or even awaken the patient from a sound
sleep. It is called unstable angina because many untreated patients end up
having a heart attack. Unstable angina may also occur in the absence of a blood
clot if the severity of the blockage (due to the atheroma and plaques) becomes
severe enough to cause a drastic decrease in blood supply to the heart
muscle.
As mentioned earlier,
angina occurs when the coronary artery is unable
to supply the demands of the heart muscle. Thus,
it seems logical that the patient's symptoms would
improve only if one was able to increase blood supply
or decrease the oxygen needs of the heart muscle,
or achieve a combination of the two. Listed below
are medications commonly used in the treatment of
angina:
Nitroglycerin and long acting
nitrates: Nitroglycerin (NTG) tablets placed
under the tongue (known as sublingual; sub=under
and lingua=tongue), is a very effective means of
treating angina. The tablet dissolves under the
tongue and may have a slightly sharp, burning or
tingling taste. Tablets which have this taste when
fresh but subsequently become tasteless may indicate
loss of effectiveness and potency. They need to
be replaced by a fresh supply when they pass the
expiration date printed on the bottle label; usually
a few months after purchase. NTG is also available
in the form of a spray. This spray pump has the
advantage of maintaining its potency for years instead
of months.
NTG placed under
the tongue dissolves quickly and demonstrates a
beneficial effect within a minute or two. It works
by dilating the coronary artery and thus improving
the supply of blood and oxygen to the heart muscle.
NTG also dilates (opens up) the veins and arteries
of the body. Dilated veins decrease the filling
of the left ventricle (LV), which in turn reduces
its workload. On the other hand, dilated arteries
of the body reduces the blood pressure and the resistance
that the LV has to overcome in pumping blood through
those arteries. A single NTG tablet should be placed
under the tongue if angina persists beyond a few
minutes after stopping activity. If the pain is
unrelieved, a second tablet is used after 5 minutes.
This is repeated at 5 minute intervals, if pain
persists. It is wise to seek medical attention if
angina is not completely resolved by the fourth
tablets. Consecutive tablets of NTG may cause dizziness
if it significantly lowers the blood pressure. In
such cases, the patient should sit or lie down.
Persistence of angina after the use of four NTG
tablets at 5 minute intervals should prompt a phone
call to your doctor. Most patients with established
or suspected coronary artery disease will be advised
to go to the emergency room or a physician's office,
depending upon the specific case.
NTG tablets placed
under the tongue are short acting and lasts only
5 to 10 minutes, which is usually a sufficient amount
of time to relieve angina. However, a different
form of NTG is needed for preventing angina from
coming on. They are known as long acting nitrates.
Long acting nitrates are available in the form of
pills that are taken one to three times a day (depending
upon the type that is prescribed) , a patch that
is applied to the skin in the morning and removed
at night, or an ointment that is placed on the skin
three to four times a day. Patients on long acting
nitrates will need to continue using NTG under the
tongue if angina occurs.
Beta Blockers: The
heart rate and blood pressure are elevated when
the body releases increased amounts of adrenaline
under moments of exertion and emotional stress.
Adrenaline the left ventricle contracts more vigorously
to provide the body with more blood flow during
the period of activity and stress. The increased
blood pressure, faster heart rate and more forceful
pumping of the left ventricle all increase the need
of oxygen by the heart. In patients with coronary
artery disease, angina occurs if the supply of oxygen
and blood cannot keep up with this increased demand
A class of medications known as beta blockers partially "insulates" the heart and blood vessels from the effects of adrenaline. This lowers the blood pressure, slows the heart and decreases the force with which the heart contracts. This in turn reduces the oxygen needs of the heart and thus helps in preventing the occurrence of angina. There are over a dozen available beta blockers with similar activities. They have also shown to be benefit in reducing the risk of a heart attack. Beta blockers are often avoided or used with great caution in patient's with slow heart beat and obstructive lung disease (emphysema, bronchitis and asthma). Fatigue, sleepiness, depression and decreased sexual libido may be experienced by some patients. Some of these symptoms may improve by changing the dose or type of beta blocker, or with the passage of time (weeks or months).
A class of medications known as beta blockers partially "insulates" the heart and blood vessels from the effects of adrenaline. This lowers the blood pressure, slows the heart and decreases the force with which the heart contracts. This in turn reduces the oxygen needs of the heart and thus helps in preventing the occurrence of angina. There are over a dozen available beta blockers with similar activities. They have also shown to be benefit in reducing the risk of a heart attack. Beta blockers are often avoided or used with great caution in patient's with slow heart beat and obstructive lung disease (emphysema, bronchitis and asthma). Fatigue, sleepiness, depression and decreased sexual libido may be experienced by some patients. Some of these symptoms may improve by changing the dose or type of beta blocker, or with the passage of time (weeks or months).
Calcium Channel Blockers:
Calcium channel blockers decrease blood pressure
and can dilate coronary arteries. For these reasons,
it is of value in the treatment of patient's with
angina; particularly in patients with high blood
pressure or in those who have not responded to a
combination of nitrates and beta blockers.
Aspirin: Aspirin is one of the least expensive and most valuable medication in the treatment of coronary artery disease. Platelets are small cells that float around in our blood stream. They are the "beavers" of the body that rush to seal any break or breach in the dam. When there is any type of damage or tear in the wall of a blood vessel, platelets collect in that area, clump together and attract formation of a clot. This seals the damage and stops bleeding when a person is injured.
Aspirin: Aspirin is one of the least expensive and most valuable medication in the treatment of coronary artery disease. Platelets are small cells that float around in our blood stream. They are the "beavers" of the body that rush to seal any break or breach in the dam. When there is any type of damage or tear in the wall of a blood vessel, platelets collect in that area, clump together and attract formation of a clot. This seals the damage and stops bleeding when a person is injured.
Unfortunately,
the same mechanism comes into play when the coronary
artery develops minor cracks in the inner lining
of the coronary artery (plaque rupture). This can
result in a blood clot that seals the artery, cuts
off blood supply to the heart muscle and leads to
a heart attack. Aspirin reduces the activity of
platelets, decreases the tendency to form clots
and is thus extremely valuable in lowering the incidence
of heart attacks in patients with coronary artery
disease. Aspirin should be avoided in patients with
an allergy to the drug. In such cases, alternative
medications may be employed.
Preventive Measures, risk
factor modification, dietary restrictions, smoking
cessation and a structured exercise program are
an important cornerstone in the treatment of coronary
artery disease.
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