Hospital therapy. Diseases of the cardiovascular system. Restrictive cardiomyopathy (lecture notes)

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Hospital therapy. Diseases of the cardiovascular system. Restrictive cardiomyopathy (lecture notes)

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LECTURE № 4. Diseases of the cardiovascular system. Restrictive cardiomyopathy

Restrictive cardiomyopathy (RCMP) - (from the Latin word restrictio - "restriction") - a group of diseases of the myocardium and endocardium, in which, as a result of pronounced fibrosis and loss of elasticity, due to various reasons, there is a fixed restriction in the filling of the ventricles in diastole.

The filling of the ventricles is carried out in the phase of early filling, followed by stabilization of intraventricular pressure. The disease is accompanied by insufficient blood filling of the heart, which further leads to the development of chronic heart failure. Restrictive cardiomyopathy is the least studied and least common of all cardiomyopathies.

RCMP includes: Lefler's parietal fibroplastic endocarditis (found in countries with a temperate climate, described by W. Loffler et al., 1936) and endomyocardial fibrosis (found in countries of tropical Africa, described by D. Bedford et E. Konstman). Previously, they were considered as two independent pathological processes. However, the pathomorphological picture in these diseases differs little.

Causes of RCM. Primary RCM is very rare, and the only proven cause of its occurrence is the so-called hypereosinophilic syndrome (Leffler's disease, Leffler's parietal fibroplastic endocarditis). It occurs mainly in men aged 30-40 years. With hypereosinophilic syndrome, inflammation of the endocardium occurs, which over time culminates in significant compaction of the endocardium and its rough adhesion to the adjacent myocardium, which leads to a sharp decrease in the extensibility of the heart muscle. Lefler's syndrome is also characterized by persistent eosinophilia for 6 months or more (1500 eosinophils per 1 mm³), damage to internal organs (liver, kidneys, lungs, bone marrow).

In the vast majority of cases, the origin of RCMP is secondary, due to other reasons, among which the most common are:

1) amyloidosis - a disease associated with a violation of protein metabolism in the body; at the same time, in the tissues of various organs, an abnormal protein (amyloid) is formed and deposited in large quantities; when the heart is damaged, amyloid causes a decrease in its contractility and extensibility;

2) hemochromatosis - a violation of iron metabolism in the body, accompanied by an increased content of iron in the blood, its excess is deposited in many organs and tissues, including the myocardium, thereby causing a decrease in its extensibility;

3) sarcoidosis - a disease of unknown etiology, characterized by the formation of cell clusters (granulomas) in organs and tissues; the lungs, liver, lymph nodes and spleen are most often affected; and developing granulomas in the myocardium lead to a decrease in its extensibility;

4) endocardial diseases (endocardial fibrosis, endocardial fibroelastosis, etc.), when there is a significant thickening and compaction of the endocardium, which also leads to a sharp limitation of myocardial extensibility. Fibroelastosis of the endocardium, in particular, can only occur in infants; this disease is not compatible with life due to the early development of severe heart failure.

Pathogenesis. With RCM, myocardial compliance suffers for various reasons. As a result, the filling of the ventricles with blood decreases and intraventricular pressure increases significantly. However, unlike HCM, the possibility of developing compensatory myocardial hypertrophy in restrictive cardiomyopathy is small. Thus, after some time, stagnation occurs in the pulmonary circulation and the pumping function of the heart decreases, which leads to gradual fluid retention in the body, the development of persistent swelling of the legs, hepatomegaly and ascites.

If the compaction of the endocardium extends to the atrioventricular valves (mitral and tricuspid), this is aggravated by the development of their insufficiency, and also leads to thrombosis in the heart cavities due to their reduced contractility and extensibility. The spread of fragments of these blood clots with the bloodstream can cause thromboembolism and blockage of large vessels, heart attacks of internal organs.

With the spread of pathological inclusions of the myocardium to the zone of the conduction system of the heart, various violations of the conduction of the cardiac impulse may appear, accompanied by the development of blockades. With RCMP, various types of arrhythmias are also quite often observed.

Based on the above, we can conclude that the disease from a pathogenetic point of view proceeds in 3 stages.

Stage I - necrotic - eosinophilic infiltration of the myocardium and other organs.

Stage II - thrombotic - the formation of blood clots in the cavities of the left and right ventricles, the development of thromboembolic complications and the gradual thickening of the endocardium mainly in the apical regions and near the atrioventricular valves.

Stage III - fibrous, characterized by thickening of the endocardium up to several millimeters, myocardial fibrosis is expressed - mainly subendocardial areas. The cavity is partially obliterated due to organized thrombi, fibrosis of the mitral valve cusps, mitral regurgitation are noted. Pronounced atrial dilatation. Restrictive diastolic dysfunction is observed.

clinical picture. Manifestations of the disease are extremely polymorphic and are determined by symptoms of circulatory disorders in the small or large circle (depending on the predominant damage to the right or left ventricles).

Complaints may be absent or may be due to congestion in the pulmonary or systemic circulation. Patients usually complain of shortness of breath, which first appears during exercise, and as the disease progresses, shortness of breath is observed at rest. Due to a decrease in the pumping function of the heart, the patient complains of fatigue and poor tolerance to any load. Over time, swelling of the legs, an enlarged liver and dropsy of the abdomen join. Periodically, an irregular heartbeat appears, and with the development of persistent blockades, there may be fainting.

The first stage of the development of the disease (necrotic) is characterized by the appearance of fever, weight loss, cough, skin rash and tachycardia.

Diagnostics. Recognizing RCM is extremely difficult. One can speak with confidence about this pathology only after excluding a number of similar diseases (such as idiopathic myocarditis of the Abramov-Fiedler type, exudative pericarditis, valvular heart defects).

When examining patients with RCMP, symptoms characteristic of congestive heart failure (edema, hepatomegaly and ascites), as well as pronounced pulsation of the neck veins, are found. The latter is due to the difficulty of blood supply to the heart due to poor myocardial extensibility.

During auscultation, the detection of an enlarged heart, a soft late systolic murmur and a loud early III tone (due to rapid filling of the ventricles during diastole) is of great importance. Murmurs in the heart are also detected in patients with atrioventricular valve insufficiency.

An ECG study reveals moderate hypertrophy of the ventricular myocardium, as well as various disturbances in the rhythm and conduction of the heart impulse, and nonspecific changes in the T wave on the ECG.

Echocardiography is one of the most informative methods for diagnosing the disease, with its help, thickening of the endocardium, a change in the nature of the filling of the ventricles of the heart, a decrease in the pumping function of the heart, a rapid movement of the anterior leaflet of the mitral valve during diastole and a rapid early movement of the posterior wall of the left ventricle outward are detected.

Magnetic resonance imaging allows you to obtain information about the anatomy of the heart, determine pathological inclusions in the myocardium and measure the thickness of the endocardium.

When examining the parameters of central hemodynamics, an increased filling pressure in both ventricles is determined, and the final pressure in the left exceeds that in the right ventricle.

Ventriculography reveals increased contraction of the left ventricle, smooth contours of its walls, sometimes with a filling defect in the apex (evidence of obliteration). In some cases, depressions in the region of the papillary muscles are determined. There are signs of valvular insufficiency, in particular the mitral or tricuspid valve.

Differential diagnostics. In the differential diagnosis of RCM, it is very important to take into account the similarity of the disease in external manifestations with constrictive pericarditis, but the treatment method for these diseases is diametrically opposite. Intravital biopsy of the myocardium and endocardium is usually used simultaneously with cardiac probing, which allows for greater information to clarify the nature of the disease and further treatment. In extremely rare cases, when the above diagnostic methods do not allow distinguishing RCM from constrictive pericarditis, a direct inspection of the pericardium is performed on the operating table.

All patients with RCMP need a comprehensive clinical, biochemical and additional examination to determine non-cardiac causes of the disease.

Treatment. Treatment of the disease presents significant difficulties. Most drugs that are used to treat heart failure may not bring the desired results due to the fact that, due to the characteristics of the disease, it is impossible to obtain a significant improvement in myocardial compliance (in some cases, calcium ion antagonists are prescribed for these purposes). Diuretics (aldactone) are used to eliminate excess fluid in the body. To eliminate persistent conduction disorders, it may be necessary to install (implant) a permanent pacemaker.

This is caused by diseases such as sarcoidosis and hemochromatosis, leading to the development of secondary RCMP, they are subject to self-treatment. In the treatment of sarcoidosis, hormonal drugs (prednisolone, etc.) are used, and in hemochromatosis, regular bloodletting (to reduce the concentration of iron in the body). Treatment of myocardial amyloidosis is directly dependent on the causes of its occurrence. It is advisable to use anticoagulant drugs for thrombosis in the chambers of the heart.

Surgical treatment is resorted to in cases of RCMP caused by endocardial damage. During the operation, if possible, the part of the endocardium that has undergone changes is excised. In some cases, if there is insufficiency of the atrioventricular valves, their prosthesis is performed. Some forms of amyloid myocardial damage are treated with a heart transplant.

Prevention of RCMP. Unfortunately, preventive measures for this disease are limited. Mainly, early identification of potentially preventable causes of amyloidosis, sarcoidosis, hemochromatosis, etc. is necessary. To achieve these goals, annual medical examination of the population is of great importance.

Author: Mostovaya O.S.

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