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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 -177- 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 -178- 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 -180- 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. |