|
1-موضوعات
عامة
2-أشعارى
3-مختارات شعرية و قصصية
4-مقالات أدبية
5-مقالات تاريخية و سياسية
6-شخصيات
7-إسلاميات
8-عروض الكتب
9-القسم الطبى
10-طب الأسنان
11-مدوناتى الخاصة
| |
What are heart valves?
The heart consists of four chambers, two atria (upper chambers) and two
ventricles (lower chambers). There is a valve through which blood passes before
leaving each chamber of the heart. The valves prevent the backward flow of
blood. These valves are actual flaps that are located on each end of the two
ventricles (lower chambers of the heart). They act as one-way inlets of blood on
one side of a ventricle and one-way outlets of blood on the other side of a
ventricle. Each valve actually has three flaps, except the mitral valve, which
has two flaps. The four heart valves include the following:
 | tricuspid valve - located between the right atrium and the right ventricle
|
| pulmonary valve - located between the right ventricle and the pulmonary
artery |
| mitral valve - located between the left atrium and the left ventricle |
| aortic valve - located between the left ventricle and the aorta |
How do the heart valves function?
As the heart muscle contracts and relaxes, the valves open and shut, letting
blood flow into the ventricles and atria at alternate times. The following is a
step-by-step illustration of how the valves function normally in the left
ventricle:
| After the left ventricle contracts, the aortic valve closes and the mitral
valve opens, to allow blood to flow from the left atrium into the left
ventricle.
|
| As the left atrium contracts, more blood flows into the left ventricle.
|
| When the left ventricle contracts again, the mitral valve closes and the
aortic valve opens, so blood flows into the aorta. |
What is heart valve disease?
Heart valves can have one of two malfunctions:
| regurgitation
The valve(s) does not close completely, causing the blood to flow backward
instead of forward through the valve.
|
| stenosis
The valve(s) opening becomes narrowed or does not form properly, inhibiting
the ability of the heart to pump blood to the body due to the increased force
required to pump blood through the stiff (stenotic) valve(s). |
Heart valves can have both malfunctions at the same time (regurgitation and
stenosis). When heart valves fail to open and close properly, the implications
for the heart can be serious, possibly hampering the heart's ability to pump
blood adequately through the body.
What are the symptoms of heart valve disease?
Mild heart valve disease may not cause any symptoms. The following are the most
common symptoms of heart valve disease. However, each individual may experience
symptoms differently. Symptoms may vary depending on the type of heart valve
disease present and may include:
| chest pain |
| palpitations caused by irregular heartbeats |
| migraine headaches |
| fatigue |
| dizziness |
| low or high blood pressure, depending on which valve disease is present
|
| shortness of breath |
| abdominal pain due to an enlarged liver (if there is tricuspid valve
malfunction) |
Symptoms of heart valve disease may resemble other medical conditions and
problems. Always consult your physician for a diagnosis.
What causes heart valve damage?
The causes of heart valve damage vary depending on the type of disease present,
and may include the following:
| a history of rheumatic fever (now a rare disease in north America due to
effective antibiotic treatment) - a condition characterized by painful fever,
inflammation, and swelling of the joints.
|
| damage resulting from a heart attack
|
| damage resulting from an infection
|
| changes in the heart valve structure due to the aging process
|
| congenital birth defect
|
| syphilis (now a rare sexually transmitted disease in North American due to
effective treatment) - a disease characterized by progressive symptoms if not
treated. Symptoms may include small, painless sores that disappear, followed
by a skin rash, enlarged lymph nodes, headache, aching bones, appetite loss,
fever, and fatigue.
|
| myxomatous degeneration - an inherited connective tissue disorder that
weakens the heart valve tissue. |
The mitral and aortic valves are most often affected by heart valve disease.
Some of the more common heart valve diseases include:
|
Heart Valve Disease |
Symptoms and Causes |
| Bicuspid aortic
valve |
This congenital
birth defect is characterized by an aortic valve that only has two flaps
(a normal aortic valve has three flaps). If the valve becomes narrowed, it
is more difficult for the blood to flow through, and often the blood leaks
backward. Symptoms usually do not develop during childhood, but are often
detected during the adult years. |
| Ebstein's
anomaly |
When Ebstein's
anomaly is present, there is a downward displacement of the tricuspid
valve (located between the upper and lower chambers on the right side of
the heart) into the right bottom chamber of the heart (or right
ventricle). This condition is usually associated with an atrial septal
defect, an opening between the two upper chambers of the heart.
|
| Tricuspid
atresia |
When tricuspid
atresia is present, there is no tricuspid valve, therefore, no blood flows
from the right atrium to the right ventricle. Tricuspid atresia defect is
characterized by a small right ventricle, a large left ventricle,
diminished pulmonary circulation, and cyanosis (insufficient oxygen in the
blood, which can cause the skin, gums, and lips to be pale or appear blue
or gray in color. |
| Mitral valve
prolapse (also known as click-murmur syndrome, Barlow's syndrome, balloon
mitral valve, or floppy valve syndrome) |
This disease is
characterized by the bulging of one or both of the mitral valve flaps
during the contraction of the heart. One or both of the flaps may not
close properly, allowing the blood to leak backward. This may result in a
mitral regurgitation murmur. |
| Mitral valve
stenosis |
Often caused by a
past history of rheumatic fever, this condition is characterized by a
narrowing of the mitral valve opening, increasing resistance to blood flow
from the left atrium to the left ventricle. |
| Aortic valve
stenosis |
This type of valve
disease mainly occurs in the elderly and is characterized by a narrowing
of the aortic valve opening, increasing resistance to blood flow from the
left ventricle to the aorta. |
| Pulmonary
stenosis |
This condition is
characterized by a pulmonary valve that does not open sufficiently,
causing the right ventricle to pump harder. |
How is heart valve disease diagnosed?
Heart valve disease may be suspected if the heart sounds heard through a
stethoscope are abnormal. This is usually the first step in diagnosing a heart
valve disease. A characteristic heart murmur (abnormal sounds in the heart due
to turbulent blood flow) can often indicate valve regurgitation. To further
define the type of valve disease and extent of the valve damage, physicians may
use any of the following diagnostic procedures:
| electrocardiogram (ECG or EKG) - a test that records the electrical
activity of the heart, shows abnormal rhythms (arrhythmias or dysrhythmias),
and detects heart muscle damage.
|
| chest x-ray - a diagnostic test which uses invisible
electromagnetic energy beams to produce images of internal tissues, bones, and
organs onto film. An x-ray can show enlargement in any area of the heart.
|
| cardiac catheterization - this diagnostic procedure involves a
tiny, hollow tube (catheter) being inserted into an artery leading to the
heart in order to image the heart and blood vessels. This procedure is helpful
in determining the type and extent of valve blockage.
|
| transesophageal echo (TEE) - TEE is a diagnostic test that is used
to measure the sound waves that bounce off the heart, creating a graphic image
of the movement of the heart structures.
|
| radionuclide scans - these scans use radioactive imaging to view
blood flow, internal organ structure, and organ function.
|
| magnetic resonance imaging (MRI) - a diagnostic procedure that uses
a combination of large magnets, radiofrequencies, and a computer to produce
detailed images of organs and structures within the body. |
Treatment for heart valve disease:
In some cases, the only treatment for heart valve disease may be careful medical
supervision. However, other treatment options may include medication, surgery to
repair the valve, or surgery to replace the valve. Specific treatment will be
determined by your physician based on:
| your age, overall health, and medical history |
| extent of the disease |
| the location of the valve |
| your signs and symptoms |
| your tolerance for specific medications, procedures, or therapies |
| expectations for the course of the disease |
| your opinion or preference |
Treatment varies, depending on the type of heart valve disease, and may
include one, or a combination of, the following:
Medication
| Heart valve disease and
surgical procedures
A person with heart valve disease may need to
take antibiotics before undergoing dental or other surgical procedures that
cause bleeding. Antibiotics are also recommended by physicians and dentists
before routine professional teeth cleaning and other procedures involving
the gum or soft tissues of the mouth. Bacteria released during these and
other procedures may enter the bloodstream and lodge in the heart on the
vulnerable, diseased heart valve. The antibiotics help prevent against a
potentially fatal infection called endocarditis, an infection of the heart's
lining.
In addition, inform your dentist and other
physicians if you are taking any anticoagulant medication (to prevent blood
clots), because this medication can cause excessive bleeding during surgery.
Always inform your dentist and other
physician(s) if you have heart valve disease. |
In some cases, medication alone is successful in the treatment of heart valve
disease, and may include:
| Medications such as beta-blockers, digoxin, and
verapamil to reduce symptoms of heart valve
disease by controlling the heart rate and fibrillation.
|
| Medications to control blood pressure, such as
diuretics (medications that remove excess water
from the body by increasing urine output) or
vasodilators (medications which relax the blood
vessels, decreasing the force against which the
heart must pump, to reduce pressure in the lungs). |
Surgery
Surgery may be necessary to repair or replace the malfunctioning valve(s).
Surgery may include:
| Heart valve repair: In some cases, surgery on the
malfunctioning valve can help alleviate symptoms.
Examples of heart valve repair surgery include
cutting scarred flaps so they open more easily;
remodeling valve tissue that has enlarged; or
inserting prosthetic rings to help narrow a dilated
valve. In many cases, heart valve repair is preferable,
because a person's own tissues are used.
|
| Heart valve replacement: When heart valves are
severely malformed or destroyed, they may need
to be replaced with a new mechanism. Replacement
valve mechanisms fall into two categories: tissue
(biologic) valves, which include animal valves and
donated human aortic valves, and mechanical
valves, which can be metal, plastic, or another
artificial mechanism. |
Another treatment option that is less invasive than valve repair/replacement
surgery is balloon valvuloplasty, a non-surgical procedure in which a special
catheter (hollow tube) is threaded into a blood vessel in the groin and guided
into the heart. The catheter, which contains a deflated balloon, is inserted
into the narrowed heart valve and inflated, stretching the valve open. The
balloon is then removed. This procedure is often used to treat pulmonary
stenosis and, in some cases, aortic stenosis
|
