Tuesday, May 7, 2013

Mitral valve prolapse

Mitral valve prolapse
   Mitral valve prolapse - bowing of one or both mitral valve into the cavity of the left atrium during systole of the left ventricle. This is one of the most common forms of violation of valvular heart. Prolapse of the mitral valve prolapse may be accompanied by other valves or combined with other small abnormalities of the heart.   

Mitral valve prolapse is identified in 2-18% of children and adolescents, ie significantly more frequently than in adults. In diseases of the heart mitral valve prolapse recorded significantly higher: up to 37% of congenital heart defects, to 30-47% in patients with rheumatism and up to 60-100% of patients with hereditary connective tissue diseases.
Mitral valve prolapse can be detected at any age, including the neonatal period, but most often it is observed in children older than 7 years. Up to 10 years of mitral valve prolapse detected with equal frequency in boys and girls. In the older age group, mitral valve prolapse detected in 2 times more common in girls.

The etiology and pathogenesis of mitral valve prolapse

    On the origin of isolated primary (idiopathic) and secondary mitral valve prolapse.
  • The primary mitral valve prolapse associated with connective tissue dysplasia, which is manifested by other microanomalies valvular structure (changing the structure of the valve and the papillary muscles, the violation of the distribution, improper attachment, shortening or lengthening of the chords, the appearance of additional chords, etc.). Connective tissue dysplasia is influenced by a variety of pathological factors acting on the fetus during the period of fetal development (gestoses, SARS and occupational hazards in the mother, adverse environmental conditions, etc.). In 10-20% of cases of mitral valve prolapse is inherited through the maternal line. In the third families identify relatives of probands with signs of connective tissue dysplasia and / or psychosomatic illnesses. Connective tissue dysplasia may also occur myxomatous transformation of the valve leaflets associated with inherited violation of the structure of collagen, especially type III. Thus due to the excessive accumulation of acid mucopolysaccharides is the proliferation of tissue flaps (sometimes also the valve ring and chords), which has the effect of prolapse.
  • Secondary mitral valve prolapse is accompanied by or complicated by a variety of diseases. In secondary mitral valve prolapse, as in primary importance is the original of the connective tissue deficiency. Thus, it is often accompanied by some hereditary syndromes (Marfan syndrome, Ehlers-Danlos-Chernogubova, congenital contracture acromacria, osteogenesis imperfecta, elastic psevdoksantomu), and congenital heart disease, rheumatism and other rheumatic diseases, rheumatic carditis, cardiomyopathy, some forms of arrhythmia , vegetative dystonia syndrome, endocrine abnormalities (hyperthyroidism), etc. Mitral valve prolapse may be the result of acquired myxomatosis, inflammatory damage to the valve structures, disturbances of myocardial contractility and papillary muscles, valve-ventricular disproportion, asynchronous activities of the various parts of the heart that is often observed at birth and acquired diseases of the latter.

   In the formation of the clinical picture of mitral valve prolapse, of course, involved dysfunction of the autonomic nervous system. Furthermore, relevant metabolic and micronutrient deficiencies, in particular magnesium ions.

   Structural and functional deficiency of valvular heart leads to the fact that during the systole of the left ventricle is bowing mitral valve into the cavity of the left atrium. When prolapse free of folds, accompanied by incomplete coalescence in systole, auscultation record isolated mesosystolic clicks associated with excessive tension chords. Gapping leaflets or discrepancy in systole determines the appearance of systolic murmur of varying intensity, indicating the development of mitral regurgitation. Changes subvalvular apparatus (extension chords, reduced contractile papillary muscles) also create the conditions for the emergence or strengthening of mitral regurgitation. 

Classification of mitral valve prolapse

    Standard classification of mitral valve prolapse do not. In addition to the delineation of mitral valve prolapse in origin (primary or secondary) are usually distinguished by auscultation and "dumb" form, specify the location of prolapse (front, back, both leaves), the degree of severity (I degree - from 3 to 6 mm, II degree - from 6 to 9 mm, III degree - more than 9 mm), the time of occurrence in relation to systole (early, late, holosystolic), the presence and severity of mitral regurgitation. Also evaluated the state of the autonomic nervous system, determine the type of flow of mitral valve prolapse, take into account the possible complications and outcomes. 

The clinical picture of mitral valve prolapse

    Mitral valve prolapse is characterized by a variety of symptoms, depending primarily on the degree of connective tissue dysplasia and autonomic changes.   Complaints in children with mitral valve prolapse are very diverse: fatigue, headaches, dizziness, fainting, shortness of breath, pain in the heart, palpitations, feeling disruptions of the heart. Characterized by decreased physical performance, psycho-emotional lability, anxiety, irritability, anxiety, depression, and hypochondriacal reaction.   In most cases, mitral valve prolapse are different manifestations of connective tissue dysplasia: asthenic physique, tall, weight loss, increased elasticity of the skin, poor muscle development, joint hypermobility, incorrect posture, scoliosis, chest wall deformity, winged scapula, flat feet, myopia . You can find hypertelorism eyes and nipples, distinctive structure ears, arched palate, cleft sandalevidnuyu and other small abnormalities. By the visceral manifestations of connective tissue dysplasia include nephroptosis, abnormal structure of the gall bladder, etc.

   Often with mitral valve prolapse observed change in heart rate and blood pressure, mainly due to hypersympathicotonia. The boundaries of the heart is usually not extended. The most informative data auscultative: most isolated listen to clicks or a combination thereof with pozdnesistolicheskim noise, at least - isolated pozdnesistolichesky or holosystolic noise. Clicking fixed in the middle or end systole, or generally at the apex point of the fifth cardiac auscultation. They are not held beyond the region of the heart and do not exceed the volume of the tone II may be transient or permanent, appear or grow in intensity in the upright position and during exercise. Isolated pozdnesistolichesky noise (rough, "scrubbing"), listen to the apex of the heart (the best in the left lateral position), it is held in the armpit and is amplified in a vertical position. Holosystolic noise, reflecting the presence of mitral regurgitation, occupies the entire systole, is stable. Some patients listen to "squeak" of the chords associated with the vibration of the valve structures. In some cases (for "silent" version of mitral valve prolapse), auscultation no symptoms. Symptoms of secondary mitral valve prolapse is similar to that in the primary and combined with the manifestations characteristic of the underlying disease (Marfan syndrome, congenital heart disease, rheumatic heart disease, etc.).

Instrumental study of mitral valve prolapse   

On radiographs, as a rule, determine the normal or reduced size of the heart. Often show a moderate bulging arc pulmonary artery associated with disability connective tissue. The ECG is often recorded transient or persistent breach of ventricular repolarization (decrease in the amplitude of the T wave, the displacement of the segment ST), a variety of arrhythmias (tachyarrhythmias, beats, slow atrioventricular conduction), often revealed by Holter monitoring. Possible prolongation of the interval Q-T. Echocardiography is the most informative, identify systolic displacement of one (mainly the back), or both mitral valve, mitral annular excursion change, interventricular septum, and other parts of the heart, thickening and uneven contours of the valves (signs of myxomatous degeneration), microanomalies valvular structures, as well as signs of mitral regurgitation. Sometimes when echocardiography reveals dilatation of the aorta, pulmonary artery trunk, open oval window, the other valve prolapse, indicating a widespread connective tissue dysplasia. 

Diagnosis and differential diagnosis of mitral valve prolapse

    For the diagnosis of mitral valve prolapse using clinical and instrumental criteria. The main criteria - typical auscultatory and echocardiographic signs-that is crucial. Clinical history, complaints, manifestations of connective tissue dysplasia, X-ray and ECG findings contribute to the diagnosis, but are of secondary importance.

   Mitral valve prolapse must be differentiated primarily with congenital or acquired mitral valve systolic noise caused by other variants of small malformations of the heart or valvular dysfunction. Echocardiography is the most informative, promotes the correct assessment of the identified changes of heart. 

Treatment of mitral valve prolapse

    Treatment with mitral valve prolapse depends on its shape, the degree of clinical symptoms, including the nature of cardiovascular and autonomic changes, and the characteristics of the underlying disease.
  • In a "dumb" form of treatment is limited to general measures aimed at normalizing autonomic and emotional status of children without reduction exercise.
  • When auscultatory variant children satisfactorily carrying exercise and do not have significant violations of the ECG data can take exercise in the group. Exclude only exercise-related sudden movements, running, jumping. In some cases it is necessary exemption from the competition.
  • The detection of mitral regurgitation, marked disturbances of repolarization on the ECG, arrhythmia distinct needs significant limitation of physical activity with individual selection of complex physical therapy.

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