132. Myocarditis: definition, classification, etiology, pathogenesis, pathological anatomy, complications, outcomes.

Myocarditis is an inflammation of the myocardium, i.e. the muscles of the heart. It usually occurs a second time in viral, rickettsious (typhus), bacterial and protozoal infectious and infectious-allergic (rheumatism) diseases (secondary myocarditis). Idiopathic myocarditis is represented as an independent disease. Idiopathic myocarditis (Abramov-Fiedler myocarditis) is characterized by a selective inflammatory process in the myocardium (isolated myocarditis) and a severe progressive course with frequent fatal outcome. The course of the disease is acute or chronic recurrent. Etiology and pathogenesis. The allergic nature of idiopathic myocarditis is currently recognized. The progression of the disease is probably associated with autoimmunity.

Classification 1. By reason - Infectious

- Immunopathological reactions - Sarcoidosis - Giant cell myocarditis 2. According to the pathogenetic sign - Primary infectious - Infectious-allergic - Toxic-allergic 3. According to morphology, the following 4 types are distinguished depending on the prevailing processes:

• Dystrophic (destructive), characterized by the predominance of hydropic dystrophy and lysis of cardiomyocytes, with no reactive changes (areactive myolysis). In areas of muscle cell death, the reticular stroma collapses.

• Inflammatory-infiltrative, in which serous edema and interstitial inflammation develop with infiltration of the myocardial stroma by various cells — neutrophils, lymphocytes, macrophages, plasma cells. Multinucleated giant cells are found among them. Cardiomyocyte dystrophy is moderate.

• Mixed, in which a combination of destructive and inflammatory-infiltrative changes develops.

• Vascular, characterized by the predominance of vascular lesions — vasculitis, in addition, dystrophic and inflammatory-infiltrative changes of the myocardium are found.

Complications. The most frequent and dangerous are thromboembolic complications, which may be the first manifestations of myocarditis. There is also a rhythm disorder, heart failure, cardiosclerosis and even sudden cardiac death.

Outcomes: complete recovery, cardiosclerosis, death.

133. Cardiomyopathy: definition, causes, classification, pathological anatomy, complications, outcomes.

Cardiomyopathy is a group of diseases characterized by primary dystrophic changes in the myocardium. It includes various diseases of non-coronary and non-traumatic origin Primary - Hypertrophic (constrictive) – subaortic stenosis - Dilated (stagnant) - Restrictive (fibroelastosis, Lefler's endocarditis) Secondary - Alcoholic -Thyrotoxic - Amyloid - Hemochromatosis

Among the primary CMPs, there are: 1) Constrictive (hypertrophic). The etiology is hereditary. The basis of the occurrence is considered to be high sensitivity to catecholamines, high embryonic activity of the heart or a violation of the reticular skeleton of the heart. The pathogenesis is based on excessive contractile activity of the heart, hyperplasia of ultrastructures, hypertrophy of fibers, which eventually leads to dystrophy. Among the constrictive forms, a diffuse one is distinguished – thickening of the left myocardium with intact valves, endocardium and heart cavity. Muscle fibrils are randomly directed, hypertrophied. The local form is expressed in hypertrophy of the area near the aortic valve – subaortic stenosis

2) Dilation. The etiology is viral, toxic (Coxsackie and alco). The myocardium is flabby, the cavities are stretched, the myofibrils are equally hypertrophied or dystrophic. The presence of fibrous strands in the myocardium is characteristic. The heart cavity is packed with blood clots. The valve apparatus is unchanged..

3) Restrictive cardiomyopathy also captures the walls of the endocardium with the formation of fibrosis thereof and the imposition of thrombotic masses. The endocardium reduces the volume of the cavity of the left heart.

Secondary cardiomyopathy – alcoholic cardiomyopathy The heart is moderately hypertrophied, but sometimes it can have a normal mass. Macro: the heart cavities are dilated, the myocardium is flabby, the incision is yellowish due to fatty degeneration, small scars are visible. coronary arteries are more often not affected by atherosclerosis. Micro: alternation of atrophic and hypertrophied muscle fibers, fatty degeneration of cardiomyocytes, obesity of the heart. minor infiltration of Lc

Possible complications of cardiomyopathy: heart failure; arrhythmia; hypertension; myocardial infarction; thromboembolism; sudden cardiac arrest.

Secondary

Alcoholic cardiomyopathy is of the greatest importance among secondary cardiomyopathies. Its pathogenesis is primarily associated with the biological properties of ethanol — a direct toxic effect on cardiomyocytes and the effect of the metabolite of ethanol — acetaldehyde.

Morphological changes of the heart are moderate myocardial hypertrophy, expansion of the heart cavities with parietal thrombi. The myocardium is flabby, clay-like, sometimes with small scars. There are arteriosclerosis phenomena in the coronary arteries, lipid spots and stripes in the intima are possible; there are no pronounced atherosclerotic changes.

Complications of alcoholic cardiomyopathy: sudden death due to ventricular fibrillation or chronic heart failure, thromboembolic syndrome.

The outcomes depend on the cause, age and degree of the disease.