Реферат на тему Angina Pectoris Essay Research Paper ANGINA PECTORIS
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Angina Pectoris Essay, Research Paper
ANGINA PECTORIS
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CONTENTS
3 Introduction
4 The Human Heart
5 Symptoms of Coronary Heart Disease
5 Heart Attack
5 Sudden Death
5 Angina
6 Angina Pectoris
6 Signs and Symptoms
7 Different Forms of Angina
8 Causes of Angina
9 Atherosclerosis
9 Plaque
10 Lipoproteins
10 Lipoproteins and Atheroma
11 Risk Factors
11 Family History
11 Diabetes
11 Hypertension
11 Cholesterol
12 Smoking
12 Multiple Risk Factors
13 Diagnosis
14 Drug Treatment
14 Nitrates
14 Beta-blockers
15 Calcium antagonists
15 Other Medications
16 Surgery
16 Coronary Bypass Surgery
17 Angioplasty
18 Self-Help
20 Type-A Behaviour Pattern
21 Cardiac Rehab Program
22 Conclusion
23 Diagrams and Charts
26 Bibliography
INTRODUCTION
In today’s society, people are gaining medical knowledge at
quite a fast pace. Treatments, cures, and vaccines for various
diseases and disorders are being developed constantly, and yet,
coronary heart disease remains the number one killer in the
world.
The media today concentrates intensely on drug and alcohol
abuse, homicides, AIDS and so on. What a lot of people are not
realizing is that coronary heart disease actually accounts for
about 80% of all sudden deaths. In fact, the number of deaths
from heart disease approximately equals to the number of deaths
from cancer, accidents, chronic lung disease, pneumonia and
influenza, and others, COMBINED.
One of the symptoms of coronary heart disease is angina
pectoris. Unfortunately, a lot of people do not take it
seriously, and thus not realizing that it may lead to other
complications, and even death.THE HUMAN HEART
In order to understand angina, one must know about our own
heart. The human heart is a powerful muscle in the body which is
worked the hardest. A double pump system, the heart consists of
two pumps side by side, which pump blood to all parts of the
body. Its steady beating maintains the flow of blood through the
body day and night, year after year, non-stop from birth until
death.
The heart is a hollow, muscular organ slightly bigger than a
person’s clenched fist. It is located in the centre of the chest,
under the breastbone above the sternum, but it is slanted
slightly to the left, giving people the impression that their
heart is on the left side of their chest.
The heart is divided into two halves, which are further
divided into four chambers: the left atrium and ventricle, and
the right atrium and ventricle. Each chamber on one side is
separated from the other by a valve, and it is the closure of
these valves that produce the “lubb-dubb” sound so familiar to
us. (see Fig. 1 – The Structure of the Heart)
Like any other organs in our body, the heart needs a supply
of blood and oxygen, and coronary arteries supply them. There are
two main coronary arteries, the left coronary artery, and the
right coronary artery. They branch off the main artery of the
body, the aorta. The right coronary artery circles the right side
and goes to the back of the heart. The left coronary artery
further divides into the left circumflex and the left anterior
descending artery. These two left arteries feed the front and the
left side of the heart. The division of the left coronary artery
is the reason why doctors usually refer to three main coronary
arteries. (Fig. 2 – Coronary Arteries)SYMPTOMS OF CORONARY HEART DISEASE
There are three main symptoms of coronary heart disease:
Heart Attack, Sudden Death, and Angina.
Heart Attack
Heart attack occurs when a blood clot suddenly and
completely blocks a diseased coronary artery, resulting in the
death of the heart muscle cells supplied by that artery.
Coronary and Coronary Thrombosis2 are terms that can refer to a
heart attack. Another term, Acute myocardial infarction2, means
death of heart muscle due to an inadequate blood supply.
Sudden Death
Sudden death occurs due to cardiac arrest. Cardiac arrest
may be the first symptom of coronary artery disease and may occur
without any symptoms or warning signs. Other causes of sudden
deaths include drowning, suffocation, electrocution, drug
overdose, trauma (such as automobile accidents), and stroke.
Drowning, suffocation, and drug overdose usually cause
respiratory arrest which in turn cause cardiac arrest. Trauma may
cause sudden death by severe injury to the heart or brain, or by
severe blood loss. Stroke causes damage to the brain which can
cause respiratory arrest and/or cardiac arrest.
Angina
People with coronary artery disease, whether or not they
have had a heart attack, may experience intermittent chest pain,
pressure, or discomforts. This situation is known as angina
pectoris. It occurs when the narrowing of the coronary arteries
temporarily prevents an adequate supply of blood and oxygen to
meet the demands of working heart muscles.ANGINA PECTORIS
Angina Pectoris (from angina meaning strangling, and
pectoris meaning breast) is commonly known simply as angina and
means pain in the chest. The term “angina” was first used during
a lecture in 1768 by Dr. William Heberden. The word was not
intended to indicate “pain,” but rather “strangling,” with a
secondary sensation of fear.
Victims suffering from angina may experience pressure,
discomfort, or a squeezing sensation in the centre of the chest
behind the breastbone. The pain may radiate to the arms, the
neck, even the upper back, and the pain may come and go. It
occurs when the heart is not receiving enough oxygen to meet an
increased demand.
Angina, as mentioned before, is only temporarily, and it
does not cause any permanent damage to the heart muscle. The
underlying coronary heart disease, however, continues to progress
unless actions are taken to prevent it from becoming worse.
Signs and Symptoms
Angina does not necessarily involve pain. The feeling varies
from individuals. In fact, some people described it as “chest
pressure,” “chest distress,” “heaviness,” “burning feeling,”
“constriction,” “tightness,” and many more. A person with angina
may feel discomforts that fit one or several of the following
descriptions:
- Mild, vague discomfort in the centre of the chest, which
may radiate to the left shoulder or arm
- Dull ache, pins and needles, heaviness or pains in the
arms, usually more severe in the left arm
- Pain that feels like severe indigestion
- Heaviness, tightness, fullness, dull ache, intense
pressure, a burning, vice-like, constriction, squeezing
sensation in the chest, throat or upper abdomen
- Extreme tiredness, exhaustion of a feeling of collapse
- Shortness of breath, choking sensation
- A sense of foreboding or impending death accompanying
chest discomfort
- Pains in the jaw, gums, teeth, throat or ear lobe
- Pains in the back or between the shoulder blades Angina can be so severe that a person may feel frightened,
or so mild that it might be ignored. Angina attacks are usually
short, from one or two minutes to a maximum of about four to
five. It usually goes away with rest, within a couple of minutes,
or ten minutes at the most.
Different Forms of Angina
There are several known forms of angina. Brief pain that
comes on exertion and leave fairly quickly on rest is known as
stable angina. When angina pain occurs during rest, it is called
unstable angina. The symptoms are usually severe and the coronary
arteries are badly narrowed. If a person suffers from unstable
angina, there is a higher risk for that person to develop heart
attacks. The pain may come up to 20 times a day, and it can wake
a person up, especially after a disturbing dream.
Another type of angina is called atypical or variant angina.
In this type of angina, pain occurs only when a person is resting
or asleep rather than from exertion. It is thought to be the
result of coronary artery spasm, a sort of cramp that narrows the
arteries.
Causes of Angina
The main cause of angina is the narrowing of the coronary
arteries. In a normal person, the inner walls of the coronary
arteries are smooth and elastic, allowing them to constrict and
expand. This flexibility permits varying amounts of oxygenated
blood, appropriate to the demand at the time, to flow through the
coronary arteries. As a person grows older, fatty deposits will
accumulate on the artery walls, especially if the linings of the
arteries are damaged due to cigarette smoking or high blood
pressure.
As more and more fatty materials build up, they form plaques
which causes the arteries to narrow and thus restricting the flow
of blood. This process is known as atherosclerosis. However,
angina usually does not occur until about two-thirds of the
artery’s diameter is blocked. Besides atherosclerosis, there are
other heart conditions resulting in the starvation of oxygen of
the heart, which also causes angina.
The nerve factor – The arteries are supplied with nerves,
which allow them to be controlled directly by the brain,
especially the hypothalamus – an area at the centre of the brain
which regulates the emotions. The brain controls the expanding
and narrowing of the arteries when necessary. The pressures of
modern life: aggression, hostility, never-ending deadlines,
remorseless, competition, unrest, insecurity and so on, can
trigger this control mechanism. When you become emotional, the chemicals that are released,
such as adrenaline, noradrenaline, and serotonin, can cause a
further constriction of the coronary arteries. The pituitary
gland, a small gland at the base of the brain, under the control
of the hypothalamus, can signal the adrenal glands to increase
the production of stress hormones such as cortisol and adrenaline
even further.
Coronary spasm – Sudden constrictions of the muscle layer in
an artery can cause platelets to stick together, temporarily
restricting the flow of flow. This is known as coronary spasm.
Platelets are minute particles in the blood, which play an
essential role both in the clotting process and in repairing any
damaged arterial walls. They tend to clump together more easily
when the blood is full of chemicals released during arousal, such
as cortisol and others.
Coronary spasm causes the platelets to stick together and to
the wall of the artery, while substances released by the
platelets as they stick together further constrict the blood
vessels. If the artery is already narrowed, this can have a
devastating effect as it drastically reduces the blood flow.
(Fig. 3 – Spasm in a coronary artery)
When people are very tense, they usually overbreathe or hold
their breath altogether. Shallow, irregular but rapid breathing
washes out carbon dioxide from the system and the blood will become
over-oxygenated. One might think that the more oxygen in the blood
the better, but overloaded blood actually does not give up oxygen
as easily, therefore the amount of oxygen available to the heart is
reduced. Carbon dioxide is present in the blood in the form of
carbonic acid, when there is a loss in carbonic acid, the blood
becomes more basic, or alkaline, which leads to spasm of blood
vessels, almost certainly in the brain but also in the heart.ATHEROSCLEROSIS
The coronary arteries may be clogged with atherosclerotic
plaques, thus narrowing the diameter. Plaques are usually
collections of connection tissue, fats, and smooth muscle cells.
The plaque project into the lumen, the passageway of the artery,
and interfere with the flow of blood. In a normal artery, the
smooth muscle cells are in the middle layer of the arterial wall;
in atherosclerosis they migrate into the inner layer. The reason
behind their migration could hold the answers to explain the
existence of atherosclerosis. Two theories have been developed for
the cause of atherosclerosis.
The first theory was suggested by German pathologist Rudolf
Virchow over 100 years ago. He proposed that the passage of fatty
material into the arterial wall is the initial cause of
atherosclerosis. The fatty material, especially cholesterol, acts
as an irritant, and the arterial wall respond with an outpouring of
cells, creating atherosclerotic plaque.
The second theory was developed by Austrian pathologist Karl
von Rokitansky in 1852. He suggested that atherosclerotic plaques
are aftereffects of blood-clot organization (thrombosis). The clot
adheres to the intima and is gradually converted to a mass of
tissue, which evolves into a plaque.
There are evidences to support the latter theory. It has been
found that platelets and fibrin (a protein, the final product in
thrombosis) are often found in atherosclerotic plaques, also found
are cholesterol crystals and cells which are rich in lipid. The
evidence suggests that thrombosis may play a role in
atherosclerosis, and in the development of the more complicated
atherosclerotic plaque. Though thrombosis may be important in
initiating the plaque, an elevated blood lipid level may accelerate
arterial narrowing.
Plaque
Inside the plaque is a yellow, porridge-like substance,
consisting of blood lipids, cholesterol and triglycerides. These
lipids are found in the bloodstream, they combine with specific
proteins to form lipoproteins. All lipoprotein particles contain
cholesterol, triglycerides, phospholipids, and proteins, but the
proportion varies in different particles.Lipoproteins
Lipoproteins all vary in size. The largest lipoproteins are
called Chylomicra, and consist mostly of triglycerides. The next in
size are the pre-beta-lipoproteins, then the beta lipoproteins. As
their size decreases, so do their concentration of triglycerides,
but the smaller they are, the more cholesterol they contain. Pre-
beta-lipoproteins are also known as low density lipoproteins (LDL),
and beta lipoproteins are also called very low density lipoproteins
(VLDL). They are most significant in the development of atheroma.
The smallest lipoprotein particles, the alpha lipoproteins, contain
a low concentration of cholesterol and triglycerides, but a high
level of proteins, and are also known as high density lipoproteins
(HDL). They are thought to be protective against the development of
atherosclerotic plaque. In fact, they are transported to the liver
rather than to the blood vessels.
Lipoproteins and Atheroma
The theory is that lipoproteins pass between the lining cells
of the arteries and some of them accumulate underneath. All except
the chylomicra, which are too big, have a chance to accumulate. The
protein in the lipoproteins are broken down by enzymes, leaving
behind the cholesterol and triglycerides. These fats are trapped
and set up a small inflammatory reaction. The alpha particles do
not react with the enzymes are returned to the circulation. RISK FACTORS
There are several risk factors that contribute to the
development of atherosclerosis and angina: Family history,
Diabetes, Hypertension, Cholesterol, and Smoking.
Family History
We all carry approximately 50 genes that affect the function
and structure of the heart and blood vessels. Genetics can
determine one’s risk of having heart disease. There are many cases
today where heart disease runs in a family, for many generations.
Diabetes
Diabetics are at least twice as likely to develop angina than
nondiabetics, and the risk is higher in women than in men. Diabetes
causes metabolic injury to the lining of arteries, as a result, the
tiny blood vessels that nourish the walls of medium-size arteries
throughout the body, including the coronary arteries, become
defective. These microscopic vessels become blocked, impeding the
delivery of blood to the lining of the larger arteries, causing
them to deteriorate, and artherosclerosis results.
Hypertension
High blood pressure directly injures the artery lining by
several mechanisms. The increased pressure compresses the tiny
vessels that feed the artery wall, causing structural changes in
these tiny arteries. Microscopic fracture lines then develop in the
arterial wall. The cells lining the arteries are compressed and
injured, and can no longer act as an adequate barrier to
cholesterol and other substances collecting in the inner walls of
the blood vessels.
Cholesterol
Cholesterol has become one of the most important issues in the
last decade. Reducing cholesterol intake can directly decrease
one’s risk of developing heart disease, and people today are more
conscious of what they eat, and how much cholesterol their foods
contain.
Cholesterol causes atherosclerosis by progressively narrowing
the arteries and reduces blood flow. The building up of fatty
deposits actually begins at an early age, and the process
progresses slowly. By the time the person reaches middle-age, a
high cholesterol level can be expected.Smoking
It has been proven that about the only thing smoking do is
shorten a person’s life. Despite all the warnings by the surgeon
general, people still manage to find an excuse to quit smoking.
Cigarette smoke contains carbon monoxide, radioactive
polonium, nicotine, arsenious oxide, benzopyrene, and levels of
radon and molybdenum that are TWENTY times the allowable limit for
ambient factory air. The two agents that have the most significant
effect on the cardiovascular system are carbon monoxide and
nicotine.
Nicotine has no direct effect on the heart or the blood
vessels, but it stimulates the nerves on these structures to cause
the secretion of adrenaline. The increase of adrenaline and
noradrenaline increases blood pressure and heart rate by about 10%
for an hour per cigarette. In simpler words, nicotine causes the
heart to beat more vigorously. Carbon monoxide, on the other hand,
poisons the normal transport systems of cell membranes lining the
coronary arteries. This protective lining breaks down, exposing the
undersurface to the ravages of the passing blood, with all its
clotting factors as well as cholesterol.
Multiple Risk Factors
The five major risk factors described above do more than just
add to one another. There is a virtual multiplication effect in
victims with more than one risk factor. (Chart: Risk Factors)DIAGNOSIS
It is very important for patients to tell their doctors of the
symptoms as honestly and accurately as possible. The doctor will
need to know about other symptoms that may distinguish angina from
other conditions, such as esophagitis, pleurisy, costochondritis,
pericarditis, a broken rib, a pinched nerve, a ruptured aorta, a
lung tumour, gallstones, ulcers, pancreatitis, a collapsed lung or
just be nervous. Each of the above mentioned is capable of causing
chest pain.
A patient may take a physical examination, which includes
taking the pulse and blood pressure, listening to the heart and
lung with a stethoscope, and checking weight. Usually an
experienced cardiologist can distinguish it as a cardiac or
noncardiac situation within minutes.
There are also routine tests, such as urine and blood tests,
which can be used to determine body fat level. Blood test can also
tests for:
Anemia – where the level of haemogoblin is too low, and can
restrict the supply of blood to the heart.
Kidney function – levels of various salts, and waste products,
mainly urea and creatinine in the blood. Normally these levels
should be quite low.
There are other factors which can be tested such as salt
level, blood fat and sugar levels.
A chest x-ray provides the doctor with information about the
size of the heart. Like any other muscles in the body, if the heart
works too hard for a period of time, it develops, or enlarges.
An electrocardiogram (ECG) is the tracing of the electrical
activity of the heart. As the heart beats and relaxes, the signals
of the heart’s electrical activities are picked up and the pattern
is recorded. The pattern consists of a series of alternating
plateaus and sharp peaks. ECG can indicate if high blood pressure
has produced any strain on the heart. It can tell if the heart is
beating regularly or irregularly, fast or slow. It can also pick up
unnoticed heart attacks. A variation of the ECG is the
veterocardiogram (VCG). It performs exactly like the ECG except the
electrical activity is shown in the form of loops, or vectors,
which can be watched on a screen, printed on paper, or
photographed. What makes VCG superior to ECG is that VCG provides
a three-dimensional view of a single heart beat.DRUG TREATMENT
Angina patients are usually prescribed at least one drug. Some
of the drugs prescribed improve blood flow, while others reduce the
strain on the heart. Commonly prescribed drugs are nitrates, beta-
blockers, and Calcium antagonists. It should be noted that drugs
for angina only relief the pain, it does nothing to correct the
underlying disorder.
Nitrates
Nitroglycerine, which is the basis of dynamite, relaxes the
smooth fibres of the blood vessels, allowing the arteries to
dilate. They have a tendency to produce flushing and headaches
because the arteries in the head and other parts of the body will
also dilate.
Glyceryl trinitrate is a short-acting drug in the form of
small tablets. It is taken under the tongue for maximum and rapid
absorption since that area is lined with capillaries. It usually
relieves the pain within a minute or two. One of the drawbacks of
trinitrates is that they can be exposed too long as they
deteriorate in sunlight. Trinitrates also come in the form of
ointment or “transdermal” sticky patch which can be applied to the
skin.
Dinitrates and mononitrates are used for the prevention of
angina attacks rather than as pain relievers. They are slower
acting than trinitrates, but they have a more prolonged effect.
They have to be taken regularly, usually three to four times a day.
Dinitrates are more common than trinitrates or tetranitrates.
Beta-blockers
Beta-blockers are used to prevent angina attacks. They reduce
the work of the heart by regulating the heart beat, as well as
blood pressure; the amount of oxygen required is thereby reduced.
These drugs can block the effects of the stress hormones adrenaline
and noradrenaline at sites called beta receptors in the heart and
blood vessels. These hormones increase both blood pressure and
heart rate. Other sites affected by these hormones are known as
alpha receptors. There are side effects, however, for using beta-blockers.
Further reduction in the pumping action may drive to a heart
failure if the heart is strained by heart disease. Hands and feet
get cold due to the constriction of peripheral vessels. Beta-
blockers can sometimes pass into the brain fluids, and causes vivid
dreams, sleep disturbance, and depression. There is also a
possibility of developing skin rashes and dry eyes. Some beta-
blockers raise the level of blood cholesterol and triglycerides.
Calcium antagonists
These drugs help prevent angina by moping up calcium in the
artery walls. The arteries then become relaxed and dilated, so
reducing the resistance to blood flow, and the heart receives more
blood and oxygen. They also help the heart muscle to use the oxygen
and nutrients in the blood more efficiently. In larger dose they
also help lower the blood pressure. The drawback for calcium
antagonists is that they tend to cause dizziness and fluid
retention, resulting in swollen ankles.
Other Medications
There are new drugs being developed constantly. Pexid, for
example, is useful if other drugs fail in severe angina attacks.
However, it produces more side effects than others, such as pins
and needles and numbness in limbs, muscle weakness, and liver
damage. It may also precipitate diabetes, and damages to the
retina.SURGERY
When medications or any other means of treatment are unable to
control the pain of angina attacks, surgery is considered. There
are two types of surgical operation available: Coronary Bypass and
Angioplasty. The bypass surgery is the more common, while
angioplasty is relatively new and is also a minor operation.
Surgery is only a “last resort” to provide relief and should not be
viewed as a permanent cure for the underlying disease, which can
only be controlled by changing one’s lifestyle.
Coronary Bypass Surgery
The bypass surgery involves extracting a vein from another
part of the body, usually the leg, and uses it to construct a
detour around the diseased coronary artery. This procedure restores
the blood flow to the heart muscle.
Although this may sound risky, the death rate is actually
below 3 per cent. This risk is higher, however, if the disease is
widespread and if the heart muscle is already weakened. If the
grafted artery becomes blocked, a heart attack may occur after the
operation.
The number of bypasses depends on the number of coronary
arteries affected. Coronary artery disease may affect one, two, or
all three arteries. If more than one artery is affected, then
several grafts will have to be carried out during the operation.
About 20 per cent of the patients considered for surgery have only
one diseased vessel. In 50 per cent of the patients, there are two
affected arteries, and in 30 per cent the disease strikes all three
arteries. These patients are known to be suffering from triple
vessel disease and require a triple-bypass. Triple vessel disease
and disease of the left main coronary artery before it divides into
two branches are the most serious conditions.
The operation itself incorporates making an incision down the
length of the breastbone in order to expose the heart. The patient
is connected to a heart-lung machine, which takes over the function
of the heart and lungs during the operation and also keeps the
patient alive. At the same time, a small incision is made on the
leg to remove a section of the vein. Once the section of vein has been removed, it is attached to
the heart. One end of the vein is sewn to the aorta, while the
other end is sewn into the affected coronary artery just beyond the
diseased segment. The grafted vein now becomes the new artery
through which the blood can flow freely beyond the obstruction. The
original artery is thus bypassed. The whole operation requires
about four to five hours, and may be longer if there is more than
one bypass involved. After the operation, the patient is sent to
the Intensive Care Unit (ICU) for recovery.
The angina pain is usually relieved or controlled, partially
or completely, by the operation. However, the operation does not
cure the underlying disease, so the effects may begin to diminish
after a while, which may be anywhere from a few months to several
years. The only way patients can avoid this from happening is to
change their lifestyles.
Angioplasty
This operation is a relatively new procedure, and it is known
in full as transluminal balloon coronary angioplasty. It entails
“squashing” the atherosclerotic plaque with balloons. A very thin
balloon catheter is inserted into the artery in the arm or the leg
of a patient under general anaesthetic. The balloon catheter is
guided under x-ray just beyond the narrowed coronary artery. Once
there, the balloon is inflated with fluid and the fatty deposits
are squashed against the artery walls. The balloon is then deflated
and drawn out of the body.
This technique is a much simpler and more economical
alternative to the bypass surgery. The procedure itself requires
less time and the patient only remains in the hospital for a few
days afterward. Exactly how long the operation takes depends on
where and in how many places the artery is narrowed. It is most
suitable when the disease is limited to the left anterior
descending artery, but sometimes the plaques are simply too hard,
making them impossible to be squashed, in which case a bypass might
be necessary.SELF-HELP
The only way patients can prevent the condition of their heart
from deteriorating any further is to change their lifestyles.
Although drugs and surgery exist, if the heart is exposed to
pressure continuously and it strains any further, there will come
one day when nothing works, and all that remain is a one-way ticket
to heaven.
The following are some advices on how people can change the
way they live, and enjoy a lifetime with a healthy heart once more.
Work
A person should limit the amount of exertions to the point
where angina might occur. This varies from person to person, some
people can do just as much work as they did before developing
angina, but only at a slower pace. Try to delegate more, reassess
your priorities, and learn to pace yourself. If the rate of work is
uncontrollable, think about changing the job.
Exercise
Everyone should exercise r