Mitral stenosis - it isthmic narrowing atrioventricular holes left to resist the blood flow on the left side of the heart during ventricular diastolic relaxation.
incidence of mitral stenosis is very different in different countries and is largely dependent on the prevalence of rheumatic fever in the area.The share of pure mitral valvular lesions have an average of 60% of all heart defects, of which 75% of the defeat suffered by women.
To form the mitral valve stenosis characterized by the development of significant fibrosis valve commissure accompanied the merger, thickening and calcining wings.Along with these changes, the defeat of the mitral valve can be accompanied by some thickening, mergers and shortening of the tendon structures of chords and the formation of the funnel shape of the mitral valve.
In a situation where mitral valve stenosis develops in the background of rheumatism, morphological changes of the valve due to rheumatic heart disease
cardiohemodynamics mitral valve stenosis violated primarily due to the formation of the first barrier in the form of a narrowing of the mitral orifice.In a situation where the total area of the mitral orifice is significantly reduced, the conditions for the promotion of blood through the obstacles left side of the heart, so there is a compensatory increase in the pressure gradient blood.
In the initial stages of mitral valve stenosis compensatory pathogenetic mechanisms in the form of increased pressure in the left atrium, as well as strengthening and increasing the systole negate hemodynamic disturbances.Symptoms of high blood pressure in the left atrium in the compensated phase of mitral valve stenosis is noted only at excessive psycho-emotional and physical activity in order to ensure the increase in cardiac output.Increased pressure in the left atrium is always accompanied by an increase in pressure in the pulmonary venous system.
significant narrowing of the mitral orifice to 1 cm2 accompanied by a pronounced increase in the pressure gradient in the left atrium of 25 mm Hg higher than the levelDue to the enhanced flow of blood to the left atrium, which occurs on a background of physical and / or emotional surge occurs propotevanie excess liquid component of blood in the pulmonary alveoli and the development of symptoms of pulmonary edema.In the initial stages of this process in the body it triggers a protective mechanism in the form of a compensatory reflex Kitaeva consists in narrowing of the lumen of the pulmonary arteries of small caliber, which initially has a transitory nature, and further noted a persistent narrowing of the pulmonary arterioles.
In connection with the above compensatory effects in the pulmonary vessels occurs thickening and hardening of the vascular wall, ending in complete obliteration of the lumen.Thus, the role of "additional barrier" appears pulmonary vascular resistance.
With the depletion of compensatory mechanisms develop dilated cardiomyopathy of the right heart, and formed signs of stagnation in the systemic circulation.
Causes of mitral stenosis
most common cause of etiopathogenetic development of signs of mitral stenosis is rheumatic.Congenital isthmic narrowing of the mitral orifice is extremely rare and occurs only under the condition of attachment of tendon chords to a single papillary muscle.
degenerative mitral valve, accompanied by severe calcification of its ring, sooner or later, provokes the development of acquired mitral stenosis.Seldom, however, cause the appearance of lesions occurring valve apparatus in the form of mitral stenosis is the presence of multiple vegetations in the projection of the valve leaflets, which are observed in infective endocarditis type and myxoma of the left atrium.
Some cases of severe long-term course of endocarditis occurring against the backdrop of systemic connective tissue disorders, end the development of mitral stenosis.
Symptoms and signs of mitral stenosis
Initial signs stenotic lesion of the mitral valve is progressive shortness of breath.In the initial stage of the disease marked respiratory disorders only at excessive physical activity, and with the progression of defect is observed not only shortness of breath with minimal physical activity, but also cough.
characteristic symptom of mitral stenosis is the strengthening of respiratory disorders in a horizontal position, so to facilitate the condition of the patient takes the orthostatic position.Respiratory disorders in mitral stenosis may reach severe intensity until the occurrence of suffocation, and a copious amount of pink frothy sputum indicates the development of alveolar edema.
mitral-aortic stenosis in almost 80% of cases is accompanied by recurrent hemoptysis caused by vascular anastomoses numerous breaks under the influence of high pressure in the pulmonary veins.Also hemoptysis sometimes it occurs as a result of complications of myocardial infarction and pulmonary edema in the interstitial phase.
By reducing cardiac output observed pronounced weakness, and reduced ability to work.The emergence of various forms of cardiac arrhythmias in mitral stenosis is considered rare, but episodes of arrhythmia largely worsen the clinical manifestations of this vice.The most common form of arrhythmia is persistent atrial fibrillation.
signs of right ventricular connection congestive heart failure are expressed edema peripheral location, as well as a feeling of heaviness and discomfort in the upper right quadrant of the abdomen.Pain in the heart, and retrosternal anginal pain is no exception to the rule and does not refer to the specific features of mitral stenosis.
Although primary genesis of rheumatic mitral stenosis observed in the prevailing majority of patients, only a small percentage of cases it is possible to detect signs of typical postrevmaticheskie.The average duration of the latent period of acute rheumatic fever before the formation of narrowing of the mitral orifice with severe impairment of cardiohemodynamic decades.Acute onset of the disease is observed only in the case of atrial fibrillation, and in this case there is rapidly progressive course and the development of disability in the short term.
In the case of severe mitral stenosis have a primary objective examination of the patient allows to suspect the presence of vice, as the patient is always in position orthopnea, and patients have characteristic changes in the skin in the form of acrocyanosis and the appearance of bluish blush projected malar regions on bothparties.High pulmonary hypertension manifests the appearance of enhanced presystolic pulsing veins in the neck, and when combined with tricuspid valve revealed signs of positive venous pulse.
peculiarity of mitral stenosis is the appearance changes with the objective examination of the patient.So, palpation of the chest reveals a sharp weakening of the apical impulse as a result of the marginalization of the left ventricle hypertrophied right ventricle of the heart.Severe myocardial hypertrophy of the right heart may be accompanied by visual pulsation under the xiphoid process of the sternum, aggravated by deep inspiration.
In order diagnostic hemodynamic mitral stenosis is recommended to perform a specific palpation with the definition of voice tremor in a horizontal position with a turn to the left side.Severe narrowing of the mitral orifice accompanied by symptoms of "enhanced diastolic voice trembling" projected apex of the heart.
experienced cardiologist by applying the method of auscultatory examination of the patient can reliably establish the diagnosis, because this pathology is accompanied by specific changes in auscultation.Thus, due to limited blood filling the left ventricular cavity, there is a "popping" one tone.Severe calcification of the leaflets limits their locomotor activity, resulting in 1 sonority tone sharply weakened.When listening to the heart in a horizontal position of the patient can be observed "click mitral valve opening" at hearing the apex of the heart.The appearance of two accent colors in the projection of the pulmonary artery auscultation indicates the development of pulmonary hypertension caused by elongation of the systolic contraction of the right ventricle.
diastolic murmur auscultated as in the embodiment presystolic and mezodiastolicheskogo and its duration depends on the severity of stenotic narrowing of the mitral orifice.The best point of auscultation diastolic noise is a projection of the apex of the heart during a phase of breath exhalation.Atrial fibrillation, which often accompany mitral stenosis, promotes the disappearance presystolic component up to the complete absence of diastolic noise.
degrees of mitral stenosis
classification of mitral stenosis in stages and severity finds its application in view of the fact that each of the degrees of the disease requires the use of a particular method of treatment in order to normalize the functional state of the patient.
• The first or initial degree of mitral stenosis indicates fully intact compensatory capacity of the cardiovascular system of the patient.Compensatory mechanisms are to a slight increase of pressure in the left atrium to the level of 10 mm Hgand strengthening its systolic reduction in the area of the mitral orifice, exceeding the figure of 2.5 cm3.In the initial stage of the disease the patient's ability to work is fully preserved, and patients no significant health problems.However, when performing ray diagnostic methods not only shows signs of dilatation of the left atrium, but also the increase of its wall.
• Subkompensatornaya or second degree of mitral stenosis is characterized by the inclusion of compensatory mechanisms of intensive work of the right heart, namely, the right ventricle.In this step, it indicated the formation of so-called "first barrier" in the form of severe narrowing of the mitral orifice and 1.5 cm3.Also in this stage it indicated a significant increase in the gradient of the blood pressure in the left atrium 30 mmHgto maintain cardiac output at a constant normal level.Increasing the pressure gradient in the pulmonary capillary network is accompanied by a patients specific complaints of shortness of breath in high physical activity, occasional bouts of hemoptysis and cardiac asthma.Instrumental methods of diagnosis allows to define this category of patients signs of overload of the right heart and pulmonary hypertension.Employability patient with a second degree of mitral stenosis is somewhat limited, but saved.
• symptoms observed in the third degree mitral stenosis, due to the formation of pathogenic "second barrier," which is accompanied by the development of progressive right ventricular failure and persistent pulmonary hypertension in the arteries.Patients with third-degree mitral stenosis belong to the category of patients with a poor prognosis for rehabilitation, but life expectancy in this situation may be several decades, provided the selection of adequate medical therapy scheme.
• A feature of the fourth degree of mitral stenosis, demonstrating the progression of the disease, is a sharp increase in the functioning of the myocardium and sustained hemodynamic instability.An interesting fact is that the dimensions of the mitral orifice may be the same as in the third degree, but progressive pulmonary hypertension with organic changes in the pulmonary parenchyma is largely worsen the underlying disease.A typical specific symptoms of mitral stenosis characterized by the transition to the fourth stage is the appearance of the patient's symptoms of atrial fibrillation.Patients with fourth degree of mitral stenosis have a poor prognosis with regard to life and usually fatal disease develops within a few months.
• Fifth, or terminal degree characterized by the appearance of irreversible degenerative disorders in the circulatory system.
There is no clear gradation and timing of the duration of a particular stage of mitral stenosis, but there is a clear dependence of the disease on the timeliness of diagnosis and the provision of appropriate defect pathogenetic reasonable amount of therapeutic measures.
Provided lack of systematic therapeutic measures or non-compliance of the patient's severity of the conditions for the development of life-threatening conditions of the patient.Thus, complications of mitral stenosis are observed already at the third degree of malice and manifest themselves in the form of such pathologies:
- alveolar type of pulmonary edema (seen during the initial manifestations of the disease is extremely rare, and in severe stages of mitral stenosis);
- arrhythmias (most often occurs persistent atrial fibrillation, and the mechanism of its occurrence is due to the massive loss of cardiomyocytes and the appearance of sclerotic changes in the myocardium);
- thromboembolic vascular lesions of the brain;
- infection of bronchopulmonary apparatus as a result of prolonged stagnation changes;
- endocarditis infectious nature.
treatment of mitral stenosis
In a situation where completely absent clinical manifestations of mitral stenosis, drug activities are aimed at the prevention of infectious complications, and if necessary - to perform course bitsillinoprofilaktiki rheumatic genesis of evil.
among non-drug methods of correction of hemodynamic disturbances recommended a limitation of physical activity and eating behavior correction with the full exception of the use of salt and fluid.If mitral stenosis is in its infancy and is accompanied by bouts of atrial fibrillation, prolonged use Digoxin is recommended to reduce the number of heart beats.
In cases of episodic hemoptysis and pulmonary artery lumen tromboembolizatsii considered appropriate to an active anticoagulant therapy with heparin and the subsequent transition to indirect anticoagulants.
effective method of relief of atrial fibrillation is considered to be the type of electro-defibrillation, but this manipulation requires prior antikoagulyativnoy prepare the patient for 1 month.Severe mitral stenosis in conjunction with the violation of cardiac rhythm is not subject to cardioversion.In this case, resorted to only after depolarization transthoracic surgery blemish.
greatest efficacy in correction of hemodynamic stenosis of the mitral orifice has a surgical correction of the defect.