الفهرس 
Anatomy and physiologyOnly 14 pages are availabe for public view
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Abstract
Mitral stenosis is one of the most common causes of
the left ventricular inflow obstruction. There are many
different causes of mitral stenosis but rheumatic fever
still the main cause of the disease accounting a very high
percentage of all patients suffering from mitral stenosis,
although a difinite clinical history of rheumatic fever can
be obtained in only about 50% of patients. For unknown
reasons, it affects women much more frequently than men.
Congenital mitral stenosis, myxomatous changes, bacterial
endocarditis and lUpus erythematosis are other rare causes
of mitral stenosis.
While it is considered that the initial effect upon
the valve leaflets is rheumatic in origin, no evidence
exists that smoldering rheumatic activity is essentiai as a
cause of progression of the obstructive valve lesions years
after the initial attack or attacks. Thus it may be stated
that the rheumatic process produces the initial insult to
the valve, upon which a non-specific, self-perpetuating
process may lead to progression of the valvular stenosis.
As o~struction to mitral flow develops, the left
atrium becomes dilated and hypertrophied with formation of
thrombi which may be confined to the ieft atrial appendage
or may laminate the entire atrial wall. Thrombi may be
detached forming small emboli which embolize in somewhat
random fashion and may cause systemic emboli. Right
ventricular hypertrophy and diiatation may occur as a
reflection of high pressure in the pulmonary circuit with
characteristic congestion, distension and thickening of the
pulmonary vesseles and capillaries.
The dominant physiologic change with mitrai stenosis
is a chronic elevation in mean left atrial pressure to which
many of the symptoms of mitral stenosis can be contributed.
Mitral stenosis restricts the blood flow into the left
ventricie decreasing the cardiac output ieading to fatigue
weakness and muscular wasting with cardiac cachexia.
Arrhythmias occur frequently in mitral stenosis
especially when the right ventricle fails. Atrial
fibriiiation is the most important of these arrythllias. At
first, atrial fibrillation is paroxysmal but sooner it
becomes persistant. Thrombosis and emboli occur more
frequently in presence of atrial fibrillation.
In symptomatic patients with mitral stenosis. the
most frequent complaints are dyspnea, fatigue, palpitations
and haemoptysis. Hoarsness of voice, dysphagia. chest pain
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or a cerebral vascular accIdent from an embolus May develop.
Patients with severe mitral stenosis often complain of
paroxysmal nocturnal dyspnea and orthopnea.
The physical findings are influenced by the severity
of the stenosis, presence or absence of associated valvular
diseases. Mitral facies, malar flush, congested neck veins,
perIpheral oedema and hepatic enlargement may be present on
general examination. While inspection of apical impulse and
palpation of diastolic thrill as well as accentuated first
heart sound are usually present with tight mitral stenosis.
Auscultation characteristically reveals an accentuated first
heart sound, an opening snap and the mid-diastolic murmur
which are termed as ausculatory triad of mitral stenosis.
The radiographic findings in mitral stenosis are
clinically useful and can be diagnostic revealing the
presence of left atrial enlargement, alterations in
pulmonary venous pattern, prominence of the pulmonary
arteries and right ventricular enlargement.
The electrocardiograM can provide evidence for
underlying mitral stenosis but is not a reliable indicator
of the severity.of the lesions.
Radionuclide techniques can now provide information
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non-invasively during rest and exercise which can be useful
in evaluating the patient· with mitral stenosis before and
after surgery. Invasive procedures as cardiac catherization
and angiography will not always answer all questions and, in
fact, may raise new ones, however, they are unecessary to
estabiish the diagnosis of mitral stenosis but should be
done routinely to evaluate associated disease.
Echocardiography has become one of the most
essential non-invasive tests in cardio-vascular diseases and
has become an integral part of cardiac diagnostic
evaluation. Using M-mode. 2-D. , and continuous or pulsed
Doppler techniques are very essential in detection of
presence of mitral stenosis or other cardiac disease which
Ilay present in association with mitral stenosis.
The medical management of mitral stenosis cannot
alter the obstruction of flow through the valve. therefore,
main efforts are attempted to prevent recurrence of
rheumatic fever and bacterial endocarditis to retard further
stenosis of the valve, as well as. decrease the incidence of
cOlllplications.
Any patient with significant mitral stenosis should
be operated on, unless concolllitant disease creates a serious
operative risk. Operations for mitral stenosis are designed
to relieve the valvular obstruction.
Closed mitral commissurotomy is usually suitable for
symptomatic patients with isolated tight mitral stenosis. In
developing areas such as the Middle East and Far East where
there are unavailability of heart lung machines, closed
mitral commissurotomy is performed inspite of it becomes an
obselete in Western Counteries.
With the open mitral commissurotomy, the risk of
cerebral embolism is virtually 0 per cent, mitral
insufficiency can often be precIsely evaluated and treated
as well as a more effective commissurotomy can be performed
by separating fused chordae tindineae as well as fused
comm1ssures.
Mitral valve replacement will commonly be needed in
anyone of the following conditions: absence of opening
snap, heavy valvular calcification, or associated valvular
heart disease. The ideal prosthetic heart valve whether
bioprosthetic or mechanical valve has not yet been
developed, because each type of valves has advantages and
disadvantages,
patient.
selection should be individualized for each
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Percutaneous balloon dIlatatIon of the mitral valve
is an effective method for relIeving stenosis of the
rheumatic mitral valve, it has been used in older children
and adults and even in elderly patients with calcific mitral
stenosis with no serious complications have been reported.