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18. TONES OF HEART. MECHANISM OF HEART TONES (I, II, III, IV, V). THEORY OF HYDRAULIC SHOCK (Yu.D. SAFONOV). FACTORS DETERMINING THE STRENGTH OF HEART TONES.

Properties of the hydraulic system. The natural vibration frequency of each structure of a hydraulic system is inversely proportional to its mass. The lowest natural frequency of oscillations in the heart muscle, but this structure has a large mass. The highest frequency of natural oscillations in the lunar valves of the aorta and pulmonary artery, and their mass is the smallest. The oscillation frequency determines the pitch. The amplitude of the natural vibrations of the system structures is proportional to their mass. Consequently, a louder sound occurs during fluctuations in the muscles of the heart and blood. A functioning system (a working heart) creates a summary characteristic of sound phenomena. The whole system sounds. In the formation of I and II heart sounds, valves do not participate. And although all structures sound during the activity of the heart, high frequencies of small amplitude are quenched in the viscous medium of the blood. The answer to the paradoxical fact of sound lagging behind valve closure was found. TABLE. The source of the sound of heart sounds. So, blood is a viscous medium, so the valves in this medium do not clap, but float along with the blood stream. Accurate measurements showed that the valves close for 0.020-0.035 s before the formation of sound tones. Therefore, neither at opening nor at closing the valves of the heart generate sounds.
The sound source is hydraulic shock (hemodynamic). Water hammer is a phenomenon that occurs in a hydraulic system when the fluid flow suddenly stops as a result of an obstacle arising from the fluid. At this moment, the transition of kinetic energy (energy of motion) into potential (pressure energy), i.e. water hammer occurs. He bends the valves slightly in the direction of movement. The damper, as an elastic structure, strains and reflects a pressure wave in the opposite direction. For example: in the isometric phase of the systole, all valves are closed, a hydraulic shock to the cusps of the mitral valve is reflected by them in the opposite direction to the valve of the ventricular muscle section, and returns from the latter to the valves. The wave begins to circulate from the valve to the wall of the ventricle, which depends on the properties of the blood, the elasticity of the wall of the ventricle under the condition of the integrity of the valve and determines the normal sound of I cardiac sound. The oscillations of the valves in this case correspond to the oscillations of the described wave. Own oscillations of the valves do not appear, since they are quenched in a viscous medium of blood. So, the power cause of heart sounds is a water hammer.
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18. TONES OF HEART. MECHANISM OF HEART TONES (I, II, III, IV, V). THEORY OF HYDRAULIC SHOCK (Yu.D. SAFONOV). FACTORS DETERMINING THE STRENGTH OF HEART TONES.

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  2. Heart diseases. Coronary heart disease (CHD). Reperfusion syndrome. Hypertensive heart disease. Acute and chronic pulmonary heart.
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  3. HEART DISEASES. CORONARY ARTERY DISEASE. HYPERTENSIVE HEART DISEASE. Myocardial hypertrophy. ACUTE AND CHRONIC PULMONARY HEART
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    The boundaries of the relative dullness of the heart. Right border. First, they find the level of standing of the diaphragm on the right in order to determine the general position of the heart in the chest. On the mid-clavicular line, deep percussion determines the blunting of percussion sound, corresponding to the height of the dome of the diaphragm. Make a mark on the edge of the finger-pessimeter, facing a clear sound. Count the rib. Further quiet
  6. HEART TUMORS, HEART MANIFESTATIONS OF SYSTEMIC DISEASES, TRAUMATIC HEART INJURIES
    Wilson S. Colucci, Eugene Braunwald (Wilson S. Colucci, Eugene Braunwald) Tumors of the heart Primary tumors. Primary heart tumors are rare and, from a histological point of view, are more often classified as “benign” (Table 193-1). However, since with all heart tumors there is a potential possibility of developing deadly complications, and many patients with
  7. Clinical protocol for providing medical care to patients with chronic rheumatic heart disease (heart defects)
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  8. Diseases of the heart valves (heart defects).
    Heart defects are persistent structural changes in the heart that interfere with intracardiac and / or systemic circulation. Distinguish between acquired and congenital heart defects. Acquired heart defects are intravital and persistent lesions of the valvular apparatus of the heart and (or) the mouths of the great vessels. Congenital heart defects - the group name for structural abnormalities of valves, holes or septa in
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    Pulmonary sero-pathological condition, characterized by hypertrophy of the right ventricle caused by hypertension of the pulmonary circulation, which develops with damage to the bronchopulmonary apparatus, pulmonary vessels, chest deformity, or other diseases that impair lung function. Acute heart lay-wedge symptom complex arising from pulmonary artery thromboembolism, and with
  11. Diseases of the endocardium, myocardium, pericardium, heart valves. Cardiomyopathy Rheumatism. The concept of rheumatic diseases. Vasculitis Tumors of the heart.
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    Normally, the impulse that occurs in the sinus node spreads to the atria and ventricles, causing them to contract. Passing the centers of automatism of the 2nd and 3rd orders on its way, the impulse each time causes the discharge of these centers. Therefore, normally ectopic / that is located outside the sinus node / pacemakers do not cause heart contractions. Normal impulse propagation from the sinus node
  13. Theoretical views on the mechanism of termination of cardiac fibrillation
    The idea of ​​a possible mechanism for terminating cardiac fibrillation was closely related to an understanding of the mechanism of the fibrillation process itself. Attempts to stop fibrillation by irritation of the vagus nerves were made in due time in accordance with the consideration of this process as “overexcitation” of the heart. The success of the use of potassium salts in this regard confirmed the possibility
  14. Factors affecting ventricular function
    When discussing the function of the ventricles, the left ventricle is more often considered as a model, but the same provisions apply to the right one. The assumption of the separate functioning of the ventricles is erroneous, since their close interdependence is proved. Factors affecting systolic (expulsion) and diastolic (filling) ventricular function are distinguished. Systolic ventricular function most often
  15. The mechanism of fibrillar contractions of the heart in a relatively physiological aspect
    The first description of fibrillar contractions of the heart was the result of their accidental detection during an experimental attempt to cause a tetanic contraction of the heart muscle by exposure to it by faradic current (Hoffa, Ludwig, 1850). This attempt to comparatively study the effect of frequent electrical irritation on different muscle tissues gave an unexpected result for experimenters. Long
  16. The main mechanisms of heart rhythm disturbance
    Pathological increased automatism. Increased degree of spontaneous diastolic depolarization (phase 4 transmembrane potential). Under the influence of various factors: electrolytes, metabolites, nerve impulses, inflammation, hypoxia in this area of ​​the conductor system, the cell permeability for Na + and K + ions changes, spontaneous diastolic depolarization increases, and
  17. ELECTROPHYSIOLOGICAL MECHANISMS OF ARRHYTHMES AND HEART BLOCKADE (CLASSIFICATION AND CHARACTERISTIC)
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