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stable irregularities in the structure of the heart that interfere with its functioning.
Heart diseases may be congenital or acquired. Congenital heart diseases result from defective formation of the heart and major blood vessels during the first half of intrauterine development owing to intoxication or to certain maternal illnesses, such as rubella. They may also result from the biological effect of ionizing radiation or from chronic hypoxia of the fetus. Some forms of congenital heart disease are hereditary and include defects caused by retardation of the final development of the cardiovascular system during the first few years of life (patent ductus arteriosus and patent foramen ovale).
The four anatomical types of congenital heart disease are (1) abnormal communication between the systemic and pulmonary circulations at the level of the ventricles, auricles, or main blood vessels; (2) stenosis or obliteration of major blood vessels; (3) combined valvular disease; and (4) decrease in the number of heart chambers or marked impairment of the chambers’ functioning, and disturbance of the topography of major blood vessels. The severity of the patient’s condition is largely determined by changes in the pulmonary circulation. Hence, the forms of congenital heart disease are also grouped according to an evaluation of the patient’s condition: the pulmonary blood flow may remain unchanged, as with narrowing of the aorta, or it may decrease, as with tetralogy of Fallot, or stenosis, of the pulmonary artery. The pulmonary blood flow may also increase, as in the case of interatrial and interventricular septal defects.
Heart disease may be of the blue or white type, that is, with or without cyanosis. This depends on the group to which the disease belongs, on the direction of the blood flow from the systemic to the pulmonary circulation, on the extent of increase in pressure in the pulmonary artery, and on the condition of the cardiac muscle. In addition to cyanosis and pallor, other characteristic symptoms are dyspnea, change in size and position of the heart, heart murmurs and altered sounds during auscultation, and retarded physical development in children. If the right ventricle is markedly enlarged, a cardiac hump, or carina, may be observed in the middle of the chest. Special methods of examination are often needed to determine the type of defect: angiocardiography, aortography, or cardiac catheterization. Treatment is surgical.
Acquired heart diseases—defects of the cardiac valves and major blood vessels—result from cardiac diseases that develop after birth. The most common disease of this type is rheumatic carditis; others are atherosclerosis, bacterial endocarditis, and syphilis. These diseases are marked by insufficiency of the valves, which do not form a tight closure; by stenosis of the atrioventricular orifices of the major blood vessels; or by a combination of these defects. One or more cardiac valves may be affected. Mitral valvular disease, affecting the atrioventricular valves, is more common than disease affecting the aortic valves. Disease involving the other valves is relatively rare.
Heart diseases result in circulatory disturbances. If the valves are incompetent, the blood flows back into the heart, causing excessive blood in the chambers of the heart, hypertrophy of their muscular wall, and enlargement of the cavities. If the intracardiac openings are narrowed, the blood flow through them is reduced and the stroke volume and cardiac output decrease. The chambers above the stricture become distended with blood. Prolonged straining of the heart muscle weakens its contractile force, and cardiac insufficiency develops.
The clinical manifestations of heart disease depend on the nature and severity of the specific disease, on the course of the main disease causing the defect, and on the individual’s work and rest habits. When adequate blood flow is maintained, the patient feels well. Cardiac insufficiency is manifested by rapid pulse, dyspnea, coughing, enlargement of the liver, and edema. The diagnosis is based on the patient’s complaints, on the evidence of enlargement of the heart and of changes in its shape as determined by percussion and X-ray examination, and on the findings of auscultation and phonocardiography, procedures that detect heart murmurs and changes in heart sounds. Treatment is initiated with the appearance of symptoms of cardiac insufficiency. It includes the administration of cardiac stimulants, diuretics, and metabolic agents. Cardiac defects can be corrected by surgery; here the indications and contraindications must be carefully weighed.
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Lang, G. F. Bolezni sistemy krovoobrashcheniia, 2nd ed. Moscow, 1958.
Vishnevskii, A. A., and N. K. Galankin. Vrozhdennye poroki serdtsa i krupnykh sosudov. Moscow, 1962.
Vasilenko, V. Kh. Priobretennye poroki serdtsa. Kiev, 1972.
Wood, P. Diseases of the Heart and Circulation, 3rd ed. Philadelphia, Pa., 1968.
N. R. PALEEV AND V. A. FROLOV