The American Heart Association describes the six
major forms of CVD as coronary heart disease, hypertension, stroke, congenital
heart disease, rheumatic heart disease, and congestive heart failure. A person may have just one of these diseases
or a combination of them at the same time.
Each form exists in varying degrees of severity. All are capable of causing secondary damage
to other body organs systems.
Coronary Heart
Disease
This form of CVD, also known as coronary artery disease, involves damage to the vessels that supply blood to the heart muscle. The bulk of this blood is supplied by the
coronary arteries. Any damage to these
important vessels can cause a reduction of blood (and its vital oxygen and
nutrients) to specific areas of heart muscle.
The ultimate result of inadequate blood supply is a heart attack.
Atherosclerosis
The principle cause for the development of coronary
heart disease is atherosclerosis.
Atherosclerosis produces a narrowing of the coronary arteries. This narrowing stems from the long-term
buildup of fatty deposits, called plaque, on the inner walls of the
arteries. This buildup reduces the blood
supply to the specific portions of the heart.
Some arteries of the heart can become so blocked (concluded) that all
blood supply is stopped. Heart muscle
tissue begins to die when it is deprived of oxygen and nutrients. This damage is known as myocardial
infarction. In lay terms, this event is
called a heart attack.
Cholesterol and
Lipoproteins For many years,
scientists have known that atherosclerosis is a complicated disease that has
many causes. Some of these causes are
not well understood, but others are clearly understood. Cholesterol,
a soft, fatlike material, is manufactured in the liver and small intestine and
is necessary in the formation of sex hormones, cell membranes, bile salts, and
nerve fibers. Elevated levels of serum
cholesterol (200 mg/dl or more for young adults age 20 and older, and 1709
mg/dl or more for young people below age 20) are associated with an increased risk
for developing atherosclerosis.
About half of American adults age 20 and older exceed
the “borderline high” 200 mg/dl cholesterol level. It is estimated that nearly 40% of American
youth age 19 and below have “borderline high” cholesterol levels of 170n mg/dl
and above. About one out of five
American adults has a “high” blood cholesterol level, that is, 240 mg/dl or
greater.
Initially, most people can help lower their serum
cholesterol level by adopting three dietary changes: lowering their intake of
saturated fats, lowering their intake of dietary cholesterol, and lowering
their caloric intake to a level that does not exceed body requirements. The aim is to reduce excess fat, cholesterol,
and calories in the diet while promoting sound nutrition. By carefully following such a diet plan,
people with high serum cholesterol levels may be able to reduce their
cholesterol levels by 30 to 55 mg/dl.
However, dietary changes do not affect people equally; some will
experience greater reductions than others.
Some will not respond at all to dietary changes and may need to take
cholesterol-lowering medications and increaser their physical activity.
Cholesterol is attached to structures called
lipoproteins. Lipoproteins are particles
that circulate in the blood and transport lipids (including cholesterol). Two major classes of lipoproteins exist:
low-density lipoproteins (LDLs) and high-density lipoproteins (HDLs). A person’s total cholesterol level is chiefly
determined by the amount of the LDLs and HDLs in a measured sample of
blood. For example, a person’s total
cholesterol level of 200 mg/dl could be represented by an LDL level of 130 and
an HDL level of 40, or an LDL level of 120 and an HDL level of 60. (Note that other lipoproteins do exist and
carry some of the cholesterol in the blood.)
After much scientific study, it has been determined
that high levels of LDL are a significant promoter of atherosclerosis. This makes sense because LDLs carry the
greatest percentage of cholesterol in the bloodstream. LDLs are more likely to deposit excess
cholesterol into the artery walls. This
contributes to plaque formation.
For this reason, LDLs are often called the “bad
cholesterol.” High LDL Levels are determined partially by inheritance, but they
are also clearly associated with smoking, poor dietary patterns, obesity, and
lack of exercise.
On the other hand, high levels of HDLs are related to
a decrease in the development of atherosclerosis. HDLs are thought to transport cholesterol out
of the bloodstream. Thus HDLs have been
called the “good cholesterol.” Certain lifestyle alterations, such as quitting
smoking, reducing obesity, increasing physical activity, and replacing
saturated fats with monosaturated fats, help many people increase their level
of HDLs.
Reducing total serum cholesterol levels is a
significant step in reducing the risk of death from coronary heart disease. For people with elevated cholesterol levels,
a 1% reduction in serum cholesterol level yields about a 2% reduction in the
risk of death from heart disease. Thus a
10% to 15% cholesterol reduction can reduce risk by 20% to 30%.
Angina Pectoris
When coronary arteries become
narrowed chest pain, or angina pectoris,
is often felt. This pain results from a
reduced supply of oxygen to heart muscle tissue. Usually, angina is felt when the coronary
artery disease patient becomes stressed or exercises too strenuously. Angina reportedly can range from a feeling of
mild indigestion to a severe viselike pressure in the chest. The pain may extend from the center of the
chest to the arms and even up to the jaw.
Generally, the more severe the blockage, the more pain is felt.
Some cardiac patients relieve angina with the drug
nitroglycerin, a powerful blood vessel dilator.
This prescription drug, available in slow-release transdermal (through
the skin) patches or small pills that are placed under the patient’s tongue,
causes a major reduction in the workload of the heart muscle. Other cardiac patients may be prescribed
drugs such as calcium channel blockers or beta blockers.
Emergency Response
to Heart Crises
Heart attacks need to be fatal. The consequences of any heart attack depend
on the location of the damage to the heart, the extent to which heart muscle is
damage, and the speed with which adequate circulation is restored. Injury to the ventricles may very well prove
fatal unless medical countermeasures are immediately undertaken. The recognition of a heart attack is
critically important.
Cardiopulmonary resuscitation (CPR) is one of the
most important immediate countermeasures that trained people can use when
confronted with a victim of heart attack.
Programs sponsored by the American Red Cross and the American Heart
Association teach people how to
recognize, evaluate, and manage heart attack emergencies. CPR trainees are taught how to restore
breathing and circulation in persons requiring emergency care. Frequently, colleges offer CPR training
through courses in various departments.
With revised CPR procedures in place in 2001, we encourage students to
take a new course and become certified.
Additionally, members of the public are encouraged to obtain training in
the use of automated external defibrillators (AED). These devises are now found in most public
buildings and can markedly improve the chances of resuscitating a victim.
Diagnosis and
Coronary Repair
Once a person’s vital signs have stabilized, further
diagnostic examinations can reveal the type and extent of damage to heart
muscle. Initially an ECG might be taken,
which may be able to identify if areas of ischemia (insufficient blood flow) or
damage has occurred to the heart muscle.
Another test which may be used is echocardiography. This procedure can also detect ischemia. The diagnostic ability of both of these tests
is improved if used in conjunction with exercise (i.e., stress ECG or stress
echocardiography). This test analyses
the electrical activity of the heart. Heart catheterization, also called coronary arteriography, is a minor
surgical procedure that starts with placement of a thin plastic tube into an
arm or leg artery. This tube, called a catheter, is guided through the artery
until it reaches the coronary circulation, where a radiopaque dye is then released.
X-ray films called angiograms record
the process of the dye through the coronary arteries so that areas of blockage
can be easily identified.
Once the extent of the damage is identified, a
physician or team of physicians can decide on a medical course of action. Currently popular is an extensive form of
surgery called coronary artery bypass surgery.
An estimated 516,000 patients had bypass surgeries in 2001. The purpose of such surgery is to detour
(bypass) areas of coronary artery obstruction by usually using a section of an
artery from the patient’s chest (the internal mammary artery) and grafting it
from the aorta to a location just beyond the area of obstruction. Multiple areas of obstruction result in
double, triple, or quadruple bypasses.
Angioplasty Angioplast,
an alternative to bypass surgery, involves the surgical insertion of a doughnut-shaped
“balloon” directly into the narrowed coronary artery. When the balloon is inflated, plaque and
fatty deposits are compressed against the artery walls, widening the space
through which blood flows. The balloon
usually remains in the artery for less than 1 minute. Renarrowing of the artery will occur in about
one quarter of angioplasty patients.
Balloon angioplasty can be used for block-ages in the heart, kidneys, arms,
and legs. The decision whether to have
angioplasty or bypass surgery can be a difficult one to make. Nearly 1,050,000 angioplasty procedures were
performed in 2001.
The
FDA approved a device for clearing heart and leg arteries. This devise is called a motorized scraper. Inserted
through a leg artery and held in place by a tiny inflated balloon, this
motor-driven cutter shaves off plaque deposits from inside the artery. A nose cone in the scraper unit stores the
plaque until the device is removed.
The use of laser beams to dissolve plaque that blocks
arteries has been slowly evolving. The
FDA has approved three laser devices for use in clogged leg arteries. In 1992 the FDA approved the use of an
excimer laser for use in coronary arteries.
Aspirin
Studies released a decade age highlighted the role of aspirin in reducing the risk
of heart attack in men with no history of previous attacks. Specifically, the studies concluded that for
men with hypertension, elevated cholesterol levels, or both, taking one aspirin
per day was a significant factor in reducing their risk of heart attack. Aspirin works by making the blood less able
to clot. This reduces the likelihood of
blood vessel blockages. Presently, there is differing opinion regarding the age
at which this preventive action should begin.
The safest advice is to check with your physician before starting
aspirin therapy is also beneficial for women.
Alcohol For
years, scientists have been uncertain about the extent to which alcohol
consumption is related to a reduced risk for heart disease. The current thinking is that moderate
drinking (defined as no more than two
drinks per day for men and one drink per day for women) is related to a lower
heart disease risk. However, the benefit
is much smaller than proven risk reduction behaviors such as stopping smoking,
reducing cholesterol level, lowering blood pressure, and increasing physical
activity. Experts caution that heavy
drinking increases cardiovascular risks and that non-drinkers should not start
to drink just to reduce heart disease risk.
Heart transplants
and Artificial Hearts For approximately 30 years, surgeons have been able
to surgically replace a person’s damaged heart with that of another human
being. Although very risky, these
transplant operations have added years to the lives of a number of patients who
otherwise would have lived only a short time.
In 2001, 2,202 heart transplants have performed in the United States.
Artificial hearts have also been developed and
implanted in humans. These hearts have
extended the lives of many patients, but they have kept them unpleasantly
tethered with tubes and wires to large power source machines. However, a major
medical breakthrough took place in July 2001, when the world’s first
self-contained artificial heart was successfully implanted into a 59-year-old
patient.
hypertension
just as your car’s water pump recirculates water and
maintains water pressure, your heart recirculate blood and maintains blood
pressure. When the heart contracts,
blood is forced through your arteries and veins. Your blood pressure is a measure of the force
that your circulating blood exerts against the interior walls of your arteries
and veins.
Blood pressure is measured with a sphygmomanometer. This instrument is attached to an arm-cuff
device that can be inflated to stop the flow of blood temporarily in the
brachial artery. This artery is a major
supplier of blood to the lower arm. It
is located on the inside of the upper arm, between the biceps and triceps
muscles.
A health professional using a stethoscope will listen
for blood flow while the pressure in the cuff is released. Two pressure measurements will be recorded:
the systolic pressure is the highest blood pressure against the vessel walls
during the heart contraction, and the diastolic pressure is the lowest blood
pressure against the vessel walls when the heart relaxes (between
heartbeats). Expressed in units of
millimeters of mercury displaced on the sphygmomanometer, blood pressure is
recorded as the systolic pressure over the diastolic pressure, for example,
115/82.
Although a blood pressure of less than 120/80 is
considered “normal” for an adult, lower values do not necessarily indicate a
medical problem. In fact, many young
college women of average weight will indicate blood pressure that seem to be
relatively low (100/60, for example), yet these lowered blood pressures are
quite “normal” for them.
Hypertension refers to the consistently elevated
blood pressure. Generally, concern about
a young adult’s high blood pressure begins when he or she has a systolic
reading of 140 or above or a diastolic reading of 90 or above. Now those with prehypertension are advised to
seek lifestyle measures to prevent any further elevation in their blood
pressure. Approximately 58 million
American adults and children have hypertension.
The American Heart Association reports that African Americans, Hispanic
Americans, and American Indians have higher rates of high blood pressure than
white Americans. In contrast,
Asians/Pacific Islanders have significantly lower rates of hypertension.
Although the reasons for 90% to 95% of the cases of
hypertension are not known, the health risk produced by uncontrolled
hypertension are clearly understood.
Throughout the body, long-term hypertension makes arteries and arterioles
become less elastic and thus incapable of dilating under a heavy workload. Brittle, calcified blood vessels can burst
unexpectedly and produce serious strokes (brain accidents), kidney failure
(renal accidents), or eye damage (retina hemorrhage). Furthermore, it appears that blood clots are
more easily formed and dislodged in a vascular system affected by
hypertension. Thus hypertension can be a
cause of heart attacks. Clearly,
hypertension is a potential killer.
Ironically, despite its deadly nature, hypertension
is referred to as “the silent killer” because people with hypertension often
are not aware that they have the condition.
The cannot feel the sensation of high blood pressure. The condition does not produce dizziness,
headaches, or memory loss unless one is experiencing a medical crisis. It is estimated that approximately 30% of the
people who have hypertension do not realize they have it. Many who are aware of their hypertension do
little to control it. Only a small
percentage (34%) of people who have hypertension control, regular exercise,
relaxation training, and drug therapy.
Hypertension is not thought as a curable disease;
rather, it is a controllable disease.
Once therapy is stopped, the condition returns. As a responsible adult, use every opportunity
you can to measure your blood pressure on a regular basis.
Prevention and
Treatment
Weight reduction, physical activity, moderation in
alcohol use, and sodium restriction are often used to reduce hypertension. For overweight or obese people, a reduction
in body weight may produce a significant drop in blood pressure. Physical activity helps lower blood pressure
by expending calories (which may lead to weight loss in those who are
overweight or obese) and through other physiological changes that affect the
circulation. Moderation in alcohol
consumption (no more than 1 – 2 drinks daily) helps reduce blood pressure in
some people.
The restriction of sodium (salt) in the diet also
helps some people reduce hypertension.
Interestingly, this strategy is effective only for those who are salt
sensitive estimated to be about 25% of the population. Reducing salt intake would have little effect
on the blood pressure of the rest of the population. Nevertheless, since our daily intake of salt
vastly exceeds our need for salt, the general recommendation to curb salt
intake still makes good sense.
In recent years, behavioral scientists have reported
the success of meditation, biofeedback, controlled breathing, and muscle
relaxation exercises in reducing hypertension.
Look for further findings in these areas in the years to come.
There are literally dozens of drugs available for use
by people by people with hypertension.
Unfortunately, many patients refuse to take their medication on a
consistent basis, probably because of the mistaken notion that “you must feel
sick to be sick,” Nutritional supplements, such as calcium, magnesium,
potassium, and fish oil, have not been proven to be effective in lowering blood
pressure.
Stroke
Stroke is general term for a wide variety of crises
(sometimes called cerebrovascular
accidents [CVAs] or brain attacks) that result from blood vessel damage in
the brain. African Americans have a much
greater risk of stroke than white Americans do, probably because African
Americans have a greater likelihood of having hypertension than white
Americans. Data from 2001 indicate that
163,538 deaths and half a million new cases of stroke occurred. Just as the heart muscle needs an adequate
blood supply, so does the brain. Any
disturbance in the proper supply of oxygen and nutrients to the brain can pose
a threat.
Perhaps the common form of stroke results from the
blockage of a cerebral (brain) artery.
Similar to coronary occlusions, cerebrovascular occlusions can be
started by a clot that forms within an artery, called a thrombus, or by a clot that travels from another part of the body
to the brain, called an embolus. The resultant accidents (cerebral
thrombosis or cerebral embolism) cause more than 60% of all strokes. The portion of the brain deprived of oxygen and
nutrients can literally die.
A third type of stroke can result from an artery that
bursts to produce a crisis called cerebral
hemorrhage. Damaged, brittle
arteries can be especially susceptible to bursting when a person has
hypertension.
A fourth form of stroke is a cerebral aneurysm. An
aneurysm is a ballooning or outpouching on a weakened area of an artery. Aneurysms may occur in various locations of
the body and are not always life threatening.
The development of aneurysms is not fully understood, although there
seems to be a relationship between aneurysms ad hypertension. It is quite possible that many aneurysms are
congenital defects. In any case, when a
cerebral aneurysm bursts, a stroke results.
A person who reports any warning signs of stroke or
any mini stroke, called a transient ischemic attack (TIA), will undergo a
battery of diagnostic tests, which could include a physical examination, a
serach for possible brain tumors, tests to identify areas of the brain
affected, use of the electroencephalogram, cerebral arteriography, and the use
of the CT (computer tomography) scan or MRI (magnetic resonance imaging)
scan. Many additional tests are also
available.
Treatment of stroke patients depends on the nature
and extent of the damage. Some patients
require surgery (to repair vessels and relieve pressure) and acute care in the
hospital. Others undergo drug treatment,
especially the use of anticoagulant drugs, including aspirin and TPA (tissue
plasminogen activators; the “clot buster” drug).
The advancement made in the rehabilitation of stroke
patients are amazing. Although some
severely affected patients have little hope of improvement, our increasing
advancement in the application of computer technology to such disciplines as
speech and physical therapy offer encouraging signs for stroke patients and
their families.
Congenital
Heart Disease
A congenital defect is one that is present at
birth. The American Heart Association
estimates that each year about 40,000 babies are born with a congenital heart
defect. In 2001, 4,109 children (mostly
infants) died of congenital heart disease.
A variety of abnormalities may be produced by
congenital heart disease, including valve damage, holes in the walls of the
septum, blood vessel transposition, and an underdevelopment of the left side of
the heart. All of these problems
ultimately prevent a newborn from adequately oxygenating tissues throughout the
body. A bluish skin color (cyanosis) is
seen in some infants with such congenital heart defects. These infants are sometimes referred to as blue babies
The cause of congenital heart defects is not clearly
understood, although one cause, rubella, has
been identified. The fetuses of mothers
who contract the rubella virus during the first 3 months of pregnancy are at
great risk of developing congenital
rubella syndrome (CRS), a catch-all term for a wide variety of congenital
defects, including heart defects, deafness, cataracts, and mental retardation. Other hypotheses about the development of
congenital heart disease implicate environmental pollutants; maternal use of
drugs, including alcohol, during pregnancy; and unknown genetic factors.
Treatment of congenital defects usually requires
surgery, although some conditions may respond well to drug therapy. Defective blood vessels and certain
malformations of the heart can be surgically repaired. This surgery is so successful that many
children respond quite quickly to the increased circulation and oxygenation. Many are able to lead normal, active lives.
Rheumatic
Heart Disease
Rheumatic heart disease is the final stage in a
series of complications started by a streptococcal infection of the throat
(strep throat). This bacterial
infection, if untreated, can result in an inflammatory disease called rheumatic fever (and a related condition, scarlet fever). Rheumatic fever, joint pain, skin rashes, and
possible brain and heart damage. A
person who has had rheumatic fever is more susceptible to subsequent
attacks. Rheumatic fever tends to run in
families. Over 3,400 Americans died from
rheumatic fever and rheumatic heart disease in 2001.
Damage from rheumatic fever centers on the heart’s
valves. For some reason the bacteria
tend to proliferate in the heart valves.
Defective heart valve may fail either to open fully (stenosis) or to close fully (insufficiency). Diagnosis of valve damage might initially
come when a physician hears a backwashing or backflow of blood (a murmur). Further tests – including chest X rays,
cardiac catheterization, and echocardiography – can reveal the extent of valve
damage. Once identified, a faulty valve
can be replaced surgically with a mental or plastic artificial valve or a valve
taken from an animal’s heart.
Congestive
Heart Failure
Congestive heart failure is a condition in which the
heart lacks the strength to continue to circulate blood normally throughout the
body. In 2001, 52,828 people died from
congestive heart failure. During
congestive heart failure, the heart continues to work, but it cannot function
well enough to maintain appropriate.
Venous blood flow starts to “back up.”
Swelling occurs, especially in the legs and ankles. Fluid can collect in the lungs and cause
breathing difficulties and shortness of breath, and kidney function may be
damaged.
Congestive heart failure can result from heart damage
caused by congenital heart defects, lung disease, rheumatic fever, heart
attack, atherosclerosis, or high blood pressure. Generally, congestive heart failure is
treatable through a combined program of rest, proper diet, modified daily
activities, and the use of appropriate drugs.
Without medical care, congestive heart failure can be fatal.
Additional
Condition
The heart and blood vessels are also subject to other
pathological conditions. Tumors of the
heart, although rare, occur. Infectious
conditions involving the pericardial sac that surrounds the heart (pericarditis) and the innermost layer of
the heart (endocarditis) are more commonly seen. In addition, inflammation of the veins (phlebitis) is troublesome to some
people.
Peripheral
Artery Disease also called peripheral vascular disease (PVD), is a
blood vessel disease characterized by pathological changes to the arteries and
arterioles in the extremities (primarily the legs and feet but sometimes the
hands). These changes result from years
of damage to the peripheral blood vessels.
Important causes of PAD are cigarette smoking, a high-fat diet, obesity,
and sedentary occupations. In some
cases, PAD is aggravated by blood vessel changes resulting from diabetes.
PAD severely restricts blood flow to the
extremities. The reduction in blood flow
is responsible for leg pain or cramping during exercise, numbness, tingling,
coldness, and loss of hair in the affected limb. The most serious consequence of PAD is the
increased likelihood of developing ulcerations and tissue death. These conditions can lead to gangrene and may
eventually necessitate amputation.
The
treatment of PAD consist of multiple approaches and may include efforts to
improve blood lipid levels (through diet, exercise, or drug therapy), reduce
hypertension, reduce body weight, and eliminate smoking. Blood vessels surgery is also a possible
treatment approach.
