What is Ischaemic Heart
Disease
Heart disease, or cardiovascular disease, is a term that encompasses
a broad range of disease of the heart and blood vessels. The 3 main
cardiovascular diseases, however, are heart attack, angina and stroke.
Heart attack and angina are more specifically types of coronary heart
disease because they arise from disease of the heart's own coronary
arteries.
The ultimate symptom of cardiovasular disease is death. There are approximately
20,000 heart attacks per year in Australians aged 25 to 69, and 43% of
all deaths in 1994 in Australia were attributable to cardiovascular disease.
However death is just the final outcome. For many heart disease sufferers,
this only follows years of serious restrictions on their lifestyle due
to anginal chest pains and congestive heart failure.
The insidious process that causes narrowing and blockage of blood vessels
is known as Atherosclerosis. Slowing, halting, and even
reversing this process is the aim of most of the therapies to prevent
and treat heart disease. Although traditionally pharmaceutical agents
were the mainstay of treatment, lifestyle modifications, with particular
attention to appropriate exercise regimes, and smoking cessation are
now regarded as the cornerstone of preventive cardiology.
Properly supervised exercise programmes can be of significant benefit
to even those most severely afflicted by heart disease. The Nu-Life
Intensive Cardiac Programmes run by Neocardia and Dr Neaverson
are individually designed to help this significant group of end-stage
heart disease sufferers.
.........................................................................................
 Atherosclerosis
This is the name for the most common underlying problem in heart and
blood vessel disease. This is an artery blocking process caused when
fatty and fibre-like material called atheroma builds up on the inside
surface of the arteries. This results in affected vessels being narrower,
harder and less elastic. Ultimately, this reduces the flow of blood
to the affected organ (such as the heart and brain). Surprisingly,
the process often begins during childhood and adolescence, but it is
well known that smoking, high blood pressure, and a diet high in saturated
fat tend to speed up the development of atherosclerosis.
Of more importance than total fat and cholesterol in this process are
the levels of HDL (good cholesterol ) and Triglycerides in the blood.
The bad form of cholesterol (LDL ) comes in a variety of molecular sizes
. Very small molecules can penetrate tissues very easily because of their
size so that the LDL present as small molecules can provide cholesterol
with easy access to the arterial wall - such molecules are highly atherogenic.
In subjects with HDL levels below 1mmol/l and triglycerides above 2 mmol/l
100% of their LDL cholesterol is present as small molecules and are therefore
very prone to the development of early and severe atherosclerosis.
It is therefore very important in this group of subjects (about 33%
of Australians) to increase their HDL levels as a matter of urgency.
Unfortunately few drugs will increase the HDL levels in subjects with
low initial HDL.
The heart muscle itself needs a good supply of oxygen provided by its
own special arterial system, the coronary arteries. If atherosclerosis
narrows any of the heart's coronary blood vessels, this can lead to either angina, heart attack, or congestive heart failure.
Angina
Angina is the name given to the chest pain or discomfort occurring when
part of the heart cannot get enough oxygen to meet its demands (known
as ischaemia). Initially this occurs only during times of exertion,
the pain then going away with rest. However, as the disease progresses
it begins to occur whilst the sufferer is at rest, or even asleep.
The heart muscle is not permanently damaged by these ischaemic episodes,
but angina is a warning that the muscle is at risk and the risk of
heart attack is dramatically increased. People who experience chest
pain of this type should see their doctor immediately.
Heart Attack
With a heart attack, the sufferer's chest pain does not go away with
rest and is usually more severe in intensity. The heart muscle is permanently
damaged if medical attention is not immediately sought. If the damage
is very large, the heart may stop pumping, resulting in rapid death.
A heart attack occurs when an area of atherosclerosis suddenly changes
and blocks an already narrowed coronary artery. Blood supply to the heart
is stopped and the affected part of the muscle can die if blood flow
is not quickly restored.
Often, however, the actual cause of the blockage may develop at a site
in the artery not previously affected by atherosclerosis. This occurs
due to a rupture of the lining of the artery and consequent thrombus
formation (a blood clot) over the affected area.
Heart Failure
When sufficient heart muscle has been permanently damaged by a large heart
attack, or many small heart attacks, the heart begins to fail
as the sole pump for the body's blood circulation. The surviving heart
muscle is forced to compensate by expanding in size and strength, often
to the point of compromising it's own already impaired blood supply.
As the pump fails, blood begins to build up in the veins and leaks out
into surrounding tissues, a process known as oedema. This is most easily
seen when a sufferers ankles begin to swell as the tissue oedema pools
with gravity. The most serious consequence, however, is when oedema affects
the lungs, causing shortness of breath (especially with exertion), and
even death.
Stroke
"Stroke" is the common name for a Cerebrovascular Accident, or CVA.
This is when a blood vessel supplying the brain becomes blocked or bursts,
usually at an area in the vessel afflicted by atherosclerosis. As a result,
brain cells may be irreversibly damaged, causing paralysis of parts of the
body, speech problems, and even death.
A stroke therefore occurs by the same disease process as a heart
attack, and in fact was often called a "brain attack" in
the past. Similarly, Transient Ischaemic Attacks, or TIA's, are the
warning symptoms of an impending stroke, as angina heralds a heart
attack.
| |
