FREE ESSAY ON HEART DISEASE

HEART DISEASE

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. 
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 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. 
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 (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. 
There are several risk factors that contribute to the development of atherosclerosis and
angina: Family history, Diabetes, Hypertension, Cholesterol, and Smoking. 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. 
Diabetics are at least twice as likely to develop angina than non-diabetics, 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. High blood
pressure directly injures the artery lining in several ways. 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 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
reducing 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. 
It has been proven that about the only thing smoking does 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 harder. 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
under-surface to the tearing of the passing blood, with all its clotting factors as well
as cholesterol. 
There are some medications developed over the years to help slow the deterioration of the
heart by heart disease. These medications have different pros and cons and any person
considering taking them should weigh their options carefully.
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.
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. 
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. 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.

Angioplasty 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.
Bibliography
Patel, Chandra. FIGHTING HEART DISEASE, Toronto, Macmillan, 1988. 
Shillingford, J.P. CORONARY HEART DISEASE: THE FACTS, Oxford, Oxford University Press,
1982. 
Tiger, Steven. HEART DISEASE, New York, Julian Messner, 1986. 
Fitness 106
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