Cardiomyopathies(CMP) is a group of the heart diseases characterized by a prominent increase of the heart mass (cardiomegaly) with progressing heart failure in absence of arterial hypertension, ischemic heart disease, and valvular defects.
Cardiomyopathies is typical for young and middle aged people but can be revealed also in infants. Two types of Cardiomyopathies are differentiated – primary and secondary ones. Primary Cardiomyopathies is subdivided into 3 forms – dilatation, hypertrophic and restrictive ones.
Dilatation (or congestive) cardiomyopathy is the most frequent form of the disease which characterized by cardiomegaly with the total heart mass up to 900-1000 grams. The chambers of the heart are strikingly dilated, endocardium is slightly thickened, the myocardium is pale and flabby. In about 50% of patients, parietal thrombosis can be observed which can be the source of thromboembolism. Coronary arteries have got wide lumen without significant atherosclerosis. Microscopic examination reveals hypertrophic, dystrophic and necrotic changes of cardiomyocytes with focal or diffuse fibrosis of the myocardium; sometimes small clusters of lymphocytes can be seen. It is thought that congestive Cardiomyopathies represents itself the final stage of different pathological processes in the heart – sub clinical myocarditis, hypovitaminosis, microelementoses, proteinaceous insufficiency.
Hypertrophic cardiomyopathy has nothing in common with dilatation Cardiomyopathies and represents itself the special kind of congenital abnormalities in the form of abnormal formation of myofibrils of cardiomyocytes. Cardiomyocytes are situated chaotically that provides disability of the myocardium for normal systolic contraction. As a result of it, compensatory hypertrophy of the ventricles develops, especially of the interventricular septum. In some patients, prominent hypertrophy of the left ventricle leads to a diminution of its volume, and hypertrophy of the upper part of the interventricular septum may cause subaortic stenosis. Hypertrophic Cardiomyopathies can be observed not only in adults but also in infants.
Restrictive cardiomyopathy is the rarest form of Cardiomyopathies and usually is found in inhabitants of Africa.Morphologically restrictive Cardiomyopathies is characterized by prominent thickening (fibrosis) and calcinosis of the endocardium of both ventricles with severe diminution of their volume.
Secondary cardiomyopathies develop in amyloidosis of the heart, glycogenesis, hemochromatosis and in chronic alcoholism.
Alcoholic cardiomyopathy (AC) develops in chronic alcoholism. The heart is big due to prominent dilation of its cavities. The myocardium is flabby due to proteinaceous and especially lipid degeneration of cardiomyocytes, diffuse cardiosclerosis is also typical for AC. Electron microscopy reveals damage of mitochondria of muscle cells. The most common cause of death of alcoholics is acute or chronic heart failure.