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2EARLY NEONATAL, POSTNATAL DIAGNOSIS, DIAGNOSISAND TREATMENT FOR TETRALOGY OF
FALLOT
*Xadjimukhamedova Z.B., 2Alieva N.R.
1,2National Children's Medical Center https://doi.org/10.5281/zenodo.12502109
Tetralogy of Fallot is a complex anatomical abnormality of the heart, typically including cases 4 components: pulmonary artery stenosis, ventricular septal defect (VSD), dextroposition of the aorta and hypertrophy of the right ventricle According to the International Classification of Diseases, 10th revision, there are: Q 21.3 Tetralogy of Fallot - ventricular septal defect with stenosis or atresia of the pulmonary artery, dextroposis of the aorta and hypertrophy of the right ventricle. The first reports of vice belong to M. Stensen (1673). A.A. Kisel (1887) was the first to carry out intravital diagnosis of the defect. French doctor Etienne-Louis Arthur Fallot (1888) coined the term tetralogy for clinical designation of the four components of the "blue" disease. Tetralogy of Fallot is the most common heart defect of the "blue" type(75%), its frequency is: among all congenital heart defects - 7-13% according to clinical according to pathological data, 15-16.7%, in newborns - 5-8%, in high school age - 12-14%. Tetralogy of Fallot occurs for numerous syndromes with any type inheritance (autosomal dominant, autosomal recessive, X-linked recessive).
The clinical presentation of tetralogy of Fallot may vary, which is due to the variability of hemodynamic disorders. The severity of hemodynamic disorders and the severity of the defect in primarily determined by the degree of narrowing pulmonary artery, which can range from slight stenosis to complete atresia.
Most often, with this defect, pulmonary artery stenosis is infundibular (low, high, or in the form of diffuse hypoplasia) or combined (combination of infundibular stenosis with valve stenosis, hypoplasia of the annulus and trunk of the pulmonary artery). Atresia pulmonary valves, an extreme form of obstruction, is much less common. Anatomical obstruction of the right ventricular outflow tract can be combined with hypoplasia and stenosis of the branches of the pulmonary artery, possibly with atresia of the left branch of the pulmonary artery. Tetralogy of Fallot is characterized by a high large ventricular septal defect (perimembranous subaortic) and dextroposition aorta, that is, a displacement of the aortic mouth to the right, so that it seems to "sit astride" on the interventricular septum, and from the right ventricle there is direct access to the aortic lumen. So Thus, two blood flows enter the aorta - from the right ventricle (venous) and the left ventricle (arterial).
The fourth sign of the defect is hypertrophy right ventricle, which is secondary compensatory component. The development of right ventricular hypertrophy is particularly affected by adapting it to pressure in the aorta. With severe pulmonary artery stenosis, blood flow is low. A significant part of the venous blood from the right ventricle is discharged into the aorta, causing the child to develop general cyanosis. Reset from right to left (venous-arterial) increases in a child during physical activity, since blood flow to the heart increases significantly at this time, and blood flow through the lungs practically cannot increase due to pulmonary stenosis. As a result of this, all Excess blood entering the right ventricle is dumped into the aorta, increasing cyanosis. At physical activity oxygen saturation blood in the aorta can decrease by up to 60%. At rest the blood flow through the lungs can almost correspond to the influx, being sufficient. In that In this case, venous blood is almost not discharged into aorta, while the oxygen saturation of the blood in
systemic circulation remains high. For moderate pulmonary stenosis other hemodynamic disorders are noted. Under resting conditions, through the VSD, on the contrary, there is a discharge of blood from left to right (arteriovenous) - from the left ventricle to the right, to In this case, pulmonary blood flow will be increased. During physical activity, blood flow to the heart increases significantly, but pulmonary blood flow resulting from pulmonary stenosis remains the same as at rest. Excessive the amount of venous blood will be discharged from the right ventricle into the aorta (venous-arterial discharge).
Two opposing mechanisms of hemodynamic disturbances - from reset blood from right to left in "blue" forms of the defect before the discharge of blood from left to right with "white", milder variants of tetralogy of Fallot - cause a variety of different clinical manifestations of this defect. To manifestations extracardiac compensation of the defect includes the development of polycythemia, while the number of red blood cells can reach up to 8 T/l, the content hemoglobin increases to 250 g/l. Gradually compensatory blood circulation develops between the greater circle and the lungs, carried out mainly through dilated arteries bronchi, chest, pleura, pericardium,esophagus and diaphragm.
Early neonatal, postnatal diagnosis. A severe course of the defect with cyanosis in the neonatal period is observed in 1/3 of patients.
Cyanosis appears more often from the second half of the year life. Dyspnea-cyanotic attacks usually occur in the 2nd, 3rd years of life and are accompanied by severe weakness, deep rapid breathing, loss of consciousness. Cause the appearance of such attacks - temporary closure of the outflow tract from the right ventricle - spasm its infundibular region, resulting in all venous blood enters the VSD through the aorta and causes or enhances hypoxia of the central nervous system. At the same time it weakens intensity of systolic murmur along the left sternal border. It was noted that the weaker the noise, the more severe the anatomical variant of the defect. IN in rare cases (4-5% of cases) on the back A systolic-diastolic murmur may be heard between the shoulder blades, due to the development of collateral circulation between vessels of the systemic and pulmonary circulation. The second tone on the pulmonary artery is weakened. X-ray is determined by depletion pulmonary pattern. Small heart shadow in the shape of a boot, with a recess in the area arch of the pulmonary artery. An electrocardiogram (ECG) reveals a significant deviation of the electrical axis of the heart to the right, signs of hypertrophy of the right ventricle and right atria (increased amplitude of the P wave), slowing down the period of atrioventricular conduction. On phonocardiography (PCG) intense systolic murmur is recorded, the second the tone above the pulmonary artery is widely split, and the degree of splitting depends on the degree of stenosis of the pulmonary artery, pulmonary the second tone component is weakened. With atresia pulmonary artery murmur may not be detected.
When performing an ultrasound examination, the following changes are characteristic:
- when scanning along the long axis of the heart a violation of the continuation of the interventricular septum into the anterior wall of the aorta is determined;
- expansion of the aorta (Fig. 1) and location it is closer to the anterior chest wall; as a result of displacement, the aorta has the appearance of a "rider" aorta or "riding" aorta;
- presence of a large ventricular septal defect;
- myocardial hypertrophy and increased trabecularity of the right ventricle;
- stenosis of the right ventricular outflow tract and pulmonary artery obstruction;
- break of the ultrasonic beam during transition from the cavity of the left ventricle to the root of the aorta with M-scanning;
- turbulent flow in the right ventricle in the period of systole as a result of a shunt of blood from the left to the right ventricle;
- turbulent flow in the outflow tract of the left ventricle in diastole due to shunting of blood from the right to the left ventricle;
- increased blood flow velocity and turbulent flow in the pulmonary artery due to the presence of stenosis.
Figure 1. Cardiac examination newborn Long axis scanning hearts
The aorta (AO) is dilated, its location above the interventricular septum ("seated top of the aorta"), LV - left ventricle, LA - left atrium, RV - right ventricle. Ventricular septal defect indicated arrows.
Postnatal diagnosis Clinical:
- cyanosis, which can be observed from the first months of life, but more often appears by the age of one year and later, intensifying with physical activity, emotional stress, crying, screaming, etc., skin color with cyanosis varies from blue to purple;
- the child squats (typical of tetralogy of Fallot and rarely occurs with other "blue" defects) or lies with legs brought to the stomach;
- low birth weight, developmental delay;
- dyspnea-cyanotic (hypoxemic) attacks, during which increased cyanosis, shortness of breath, tachycardia, anxiety, weakness, and sometimes loss of consciousness develop. Duration of attacks
- from a few minutes to 10-12 hours. Possible cerebrovascular accident;
- thickening and change in the shape of nails in the form of "watch glasses" and nail phalanges ("drumsticks"), expansion of skin capillary networks on the veins and in the forehead, epigastric pulsation;
- systolic tremor in the lower part chest on the left; there may be a cardiac hump;
- the borders of the heart are expanded not only to the right, but also moderately to the left;
- upon auscultation, a typical for pulmonary artery stenosis, a rough systolic murmur, reaching a maximum in II-III intercostal spaces on the left at the sternum (can be heard in the III-IV intercostal spaces). Intensity noise varies and is inversely related to the degree of pulmonary artery stenosis.
Children with significant output obstruction of the right ventricular tract, pronounced cyanosis and a low systolic murmur are detected, and in children with a lesser degree of pulmonary stenosis arteries in the absence of cyanosis, a prolonged loud systolic sound is heard murmur, sometimes accompanied by systolic trembling of the chest in the exit area right ventricular tract;
- second sound on the pulmonary artery more often weakened or represented by an aortic component - a single-component second sound (closing of the pulmonary valve is not heard).
Paraclinical:
- clinical blood test — compensatory polycythemia due to high erythrocytosis (up to 8 T/l) and polyglobulia due to an increase in hemoglobin content (up to 250 g/l);
- X-ray: heart shape in the form wooden shoe due to the rounded, the apex raised above the diaphragm and the arch of the pulmonary artery retracted. This form heart is caused by a hypertrophied right ventricle, which occupies the entire anterior surface and pushes aside the left ventricle backwards and upwards. Right ventricular hypertrophy detected in the lateral and second oblique projections. There is a slight increase in size heart (since as a result of decreased pulmonary blood flow congestive heart failure does not develop), dilatation of the right atrium, right-sided aortic arch (in 25% of patients), increasing the transparency of the lung fields for due to depletion of the pulmonary pattern. In 1/3 of children older age of obvious impoverishment may not be, and even a slight increase and chaotic looping of the pulmonary pattern due to a pronounced collateral vascular network;
- ECG: typically pronounced deviation electrical axis of the heart to the right (angle alpha from +120° to +180°), signs of hypertrophy of the right ventricle, right atrium (increased and sharpened P wave in leads II and V1-2);
- FCG: second sound above the pulmonary artery reduced in amplitude and narrowed due to weakening of the pulmonary component. High-frequency, medium-amplitude fusiform systolic murmur with peak in the first half of systole;
- echocardiography: right position and expansion of the base of the aorta and the cavity of the right ventricle, reduction in the size of the left ventricle and left atrium, hypertrophy of the right ventricle, interruption of echo signals in the interventricular septum, narrowing of the outflow tract right ventricle.
Differential diagnosis for tetrad Fallot should be performed with transposition of the aorta and pulmonary artery, double origin of the great vessels from the right ventricle, single ventricle, two-chambered heart with pulmonary artery stenosis, common truncus arteriosus. Treatment. To relieve a dyspnea-cyanotic attack, it is recommended to position the child with the knees brought to the chest for reducing venous return of blood to the heart. Constant oxygen inhalation is carried out, cordiamine is administered subcutaneously at 0.02 ml/kg mass and 1% solution of promedol 0.1 ml per year life subcutaneously or intramuscularly. To relieve spasm of the pulmonary artery, obzidan is prescribed 0.1 mg/kg intravenously at a rate 0.005 mg/min. The use of cardiac glycosides is not recommended, as they increase tendency of infundibular stenosis to spasm.
If the measures taken are ineffective, emergency surgical intervention is performed - the application of a systemic pulmonary anastomosis (between the aorta and pulmonary artery).
Surgical treatment is indicated for all patients with tetralogy of Fallot. Radical correction of this defect at an early age ensures stable long-term survival in 98% of patients and freedom from repeated surgery in 63% of patients within 10 years.
Forecast. Average life expectancy for non-operated patients is 10-12 years. Palliative operations lengthen the life expectancy of patients, but do not improve the prognosis. After radical correction of tetralogy of Fallot in the absence of postoperative complications, the prognosis is quite satisfactory.
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