Back
to contents
Heart
Health: Lecture
These lecture notes are copied
from the multimedia version of the lecture that is posted online.
Some of this information may only make sense if you view the
multimedia slides.
Heart Health: Introduction
Heart disease is the leading
cause of death in the United States. This module will cover several
basic elements of heart anatomy and physiology. You will see
the difference between healthy hearts and diseased ones and you
will learn what you can do to prevent this most common disease.
Coronary Risk Factors:
A Coronary Risk Factor is a
predictor of your chances of having coronary heart disease. Kind
of like gambling, in which chance favors certain bets. With heart
disease it seems that disease is most common in those people
who display certain risk factors. Since this is true, it means
that the more risk factors you display in your life, the greater
the likelihood that you will end up with heart disease. This
doesn't mean that you will end up with heart disease if
you have these risk factors, and it doesn't mean that those without
risk factors are immune from disease. Risk factors are meant
to warn some people with the highest risk so that they can make
changes in their lives in order to prevent disease.
Risk factors can be of two
types: controllable and non-controllable. There is nothing you
can do to modify non-controllable risk factors, but you can modify
the risk factors that are related to lifestyle choices. These
are the controllable risk factors and you would do well to choose
to modify them in positive ways.
Non-controllable:
The Circulatory System
The vascular system, also called
the cardiovascular system, is responsible for routing blood to
various parts of the body. The blood carries essential nutrients
and oxygen to all of the cells of the body. As the heart beats,
it pushes blood out through a large blood vessel on the top of
the heart called the "aorta." The "arteries"
carry oxygen-rich blood away from the heart. These are represented
by the red vessels in the multimedia slide. After delivering
their cargo of oxygen and nutrients to the various tissues of
the body, the arteries give way to "veins" which then
carry the waste products back to the heart so they can be expelled
by the lungs. The oxygen-deficient blood carried by the veins
is represented by the blue vessels in the slide.
Blood Pump
The heart is a remarkable organ.
It beats continuously, each and every minute of every day. The
heart is made up of very specialized muscle tissue called "myocardium."
This tissue is very resilient, it must be, in order to continuously
work to provide nutrients to the body during a person's entire
life. Though the heart is very strong, many people purposefully
abuse it through the overuse of drugs and alcohol. Further harm
to the heart occurs through poor diet, stress and lack of physical
activity.
Normal Heart
The heart typically is triangular
in shape. The heart you see in the multimedia slide displays
this triangular shape and is pointed at the bottom. Notice that
there is a layer of fat which surrounds the heart. This is normal
on most body organs. This fat layer provides insulation to prevent
excessive increases or decreases in temperature, and serves as
a protective cushion to prevent injury to the heart.
On the right side of the slide
you see the inside of the aorta. You can see that the inside
of a normal blood vessel is smooth and shiny. This is to facilitate
ease of blood flow through the vessels.
Diseased Heart
This slide shows what can happen
as a result of a lifetime of abuse of the heart. Poor diet, smoking,
stress, and excessive alcohol use can cause tremendous wear and
tear on the heart. In the slide at left, you can see an unhealthy
heart. It is round and bloated. This person had congestive heart
failure. The heart becomes weak, inefficient and is of little
use in pumping blood. Typical symptoms of congestive heart failure
include swollen legs and feet and difficulty breathing. This
is a result of pooling of blood in the lower extremities and
in the lungs. A person literally drowns as a result of this fluid
accumulation in the lungs.
On the right of the slide,
you can see the effects of "atherosclerosis." Atherosclerosis
is a very common type of heart disease that results from the
accumulation of fats in the arteries. This fat builds up and
narrows the opening of the blood vessel making it more difficult
for blood to flow through. Not only is a narrowed artery more
difficult to transport blood through, but it is also more prone
to obstruction. Fat, clots and other debris can become lodged
in a narrowed opening causing a heart attack or, "myocardial
infarction."
Atherosclerosis
The heart on the left of the
slide, shows signs of prolonged deterioration. The rounded shape
demonstrates the wear and tear. Also, you will notice the fatty
buildup on the inside of one of the "coronary arteries."
The artery has been cut open so you can see the inside. Besides
the build up of "atherosclerotic plaque" you can also
see a blood clot which "occluded" the artery causing
a heart attack (myocardial infarction). An infarct is an area
of destruction, that is, a portion of the heart actually dies.
If the portion is large enough, the person will not survive.
If the person survives, the heart tissue affected by the heart
attack will scar over and the rest of the heart will compensate.
On the right half of the slide
you see a cross section of an artery that has been magnified
many times. From this view you can clearly see the buildup of
fat on the inner walls of the artery.
Stroke
A stroke is essentially the
same thing as a heart attack except that it occurs in the brain.
Blood vessels in the brain are narrowed by the build up of fat.
Eventually one becomes so narrow that it becomes blocked by some
foreign material, cutting off blood flow to an area of the brain.
As you can see from the graphic above, a stroke results in internal
bleeding. A large area of the brain may be affected due to the
lack of blood flow. As with a heart attack, a portion of the
brain dies when someone has a stroke. If the portion that dies
is large enough, the person will die.
Balloon Angioplasty
People often wonder if you
can remove or reverse the fatty buildup on the inside of arteries.
One ways is shown above. This is called "balloon angioplasty."
A thin wire is inserted into a vein in the groin area and threaded
through the blood vessels up into the heart. Computer imaging
guides doctors to the location of the narrowed artery. A balloon
is inflated inside the artery which pushes the fat away, opening
the narrowed artery. After 60 seconds or so, the balloon is deflated
and removed. Usually this procedure is only a short term solution
at best. Often, the procedure will have to be repeated within
three years.
Dr. Dean Ornish has shown that
there are more conservative ways to reverse atherosclerosis.
He has demonstrated remarkable results in heart patients on a
regimen of low-fat diet, stress management techniques and regular
exercise. Of course, this is the same type of regimen that you
can and should follow early on in life, in order to prevent atherosclerosis
altogether.
Prescription for a Healthy
Heart:
1. Don't smoke. Smoking contributes
to heart disease in many ways and is the single most preventable
cause of heart disease.
2. Eat a low fat diet. Since
heart disease is often associated with diets that are high in
fat, you should attempt to reduce many of the sources of fat
in your diet. Especially saturated fats, but also polyunsaturated
and hydrogenated fats.
3. Exercise. One of the most
important risk factors for premature death from all causes is
low fitness levels. Exercise has many benefits that can contribute
to your health and happiness. Reducing the risk of heart disease
is one of those benefits.
4. Medical exams. If you are
a male over the age of 40 or a female over the age of 45, you
should have regular medical exams. You should also seek medical
attention if you have any of the common symptoms suggestive of
heart disease: dizziness or fainting, difficultly breathing or
shortness of breath at rest or with mild exertion, and / or pain
in the chest, neck, jaw or arms.
Back
to contents