Acquired heart disease: mitral stenosis
Narrowing the opening between the left chambers of the heart,known as mitral stenosis is always organic. The main reason for the development of this acquired heart disease is rheumatic endocarditis. Mitral stenosis is much less common with endocarditis of other origin.
Narrowing of the atrioventricular orificeIt develops as a result of the fusion of the mitral valve flaps with each other, their thickening and compacting. The valve takes the form of a diaphragm with a slit-shaped hole in the middle or a funnel shape.
The area of the mitral orifice is normally 4-6 sq. Km. see Mitral stenosis leads to a change in blood flow to the heart. Hemodynamic disturbances appear when the aperture is narrowed to 1.5 square meters. see During diastole, the blood from the left atrium does not have time to completely pass into the left ventricle. Therefore, in the left atrium is a small amount of blood, to which blood is added, coming from the pulmonary veins. As a result, the atrium is filled with blood, and the pressure increases in it, which is first compensated by increased contractions and stretching of the atrium. But since the muscular wall of the atria is weak, its contractility decreases soon, blood stagnation increases, and the pressure in it is further increased. With time, blood stagnation occurs in a small circle of blood circulation, an increase in the load on the right ventricle, stagnation occurs in the system of vessels of a large circle.
Clinical picture
When the stenosis of complaints is not sharp, the patient may notbe, physical activity is not significantly limited. The first complaints, indicating the appearance of stagnation in the vessels of the small circle of blood circulation, are shortness of breath and cough - dry or with a small amount of sputum, as well as increased fatigue and palpitations. Later hemoptysis and periodic attacks of cardiac asthma appear. Pain in the heart appears in about 10% of patients.
Pulse may not be the same on both hands. This is because the enlarged left atrium squeezes the left subclavian artery, and the filling of the pulse on the left decreases. Atrial fibrillation often occurs.
Palpation above the apex of the heart is determined by the symptom of cat purring. There is a cat purring while passing blood through a modified mitral orifice.
Percussion is determined by the displacement of the boundaries of the heart up and to the right, which occurs as a result of changes in individual chambers of the heart, which receives the mitral configuration.
Auscultation of the heart is of great importance indiagnosis of the defect, since mitral stenosis has a characteristic auscultative melody. Above the top of the heart is heard a sonorous clapping first tone, diastolic noise and an additional tone formed when the mitral valve is opened. All this forms a typical auscultative melody, called the rhythm of the quail. On the basis of the heart, accent and bifurcation or the splitting of the second tone are heard, the appearance of which is associated with the stagnation of blood in the lungs.
Arterial pressure, as a rule, does not change, sometimes systolic decreases slightly and diastolic blood pressure rises.
Instrumental diagnostics
On the roentgenogram the changed configuration of the heart, called mitral, and stagnant phenomena is determined.
On ECG - signs of an increase in the chambers of the heart.
Data from the FCH repeat the results of auscultation of the heart.
A great value in the diagnosis of defects is given toechocardiography, which allows to determine the deformation of the valve, thickening and calcification of its valves, a change in the volume of the heart chambers, the thickness of the heart wall.
Treatment
Treatment of stenosis of any site requiresconducting of operative intervention. With valve stenoses, the operation consists in performing commissurotomy - dissection of the modified valve flaps. Mitral and aortic stenosis, the treatment of which is performed surgically, before the operation must be translated into a compensated stage.
