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Tetralogy of Fallot
Can Tetralogy of Fallot be cured?
With the continuous improvement of surgical techniques, the cure rate for total corrective surgery for Tetralogy of Fallot is increasing, and the mortality rate is continuously decreasing. Mild cases may have the opportunity to undergo a one-stage corrective surgery between the ages of five and nine. However, for patients with significant clinical symptoms, palliative surgery should be performed within six months after birth. Once the general condition improves and pulmonary vasculature develops, they can proceed with the corrective surgery. Overall, the cure rate for Tetralogy of Fallot is continuously improving.
Tetralogy of Fallot shadow on the radiograph
Tetralogy of Fallot is the most common cyanotic heart disease in children over the age of one, accounting for about 10 percent of all congenital heart diseases. Tetralogy of Fallot includes four anatomical abnormalities: a ventricular septal defect, right ventricular outflow tract obstruction, an overriding aorta, and right ventricular hypertrophy. In patients diagnosed through X-ray, the heart size is often within normal limits, typically appearing boot-shaped, with markedly reduced pulmonary vascular markings. The aortic arch may be located on the right side, and the ascending aorta is usually dilated. Patients with rich collateral circulation display prominent pulmonary markings.
Tetralogy of Fallot cyanosis cause
Tetralogy of Fallot, due to a ventricular septal defect combined with right ventricular outflow tract narrowing, can display left-to-right, bidirectional, or even right-to-left shunting at the ventricular level. Patients with mild pulmonary stenosis can have left-to-right shunting and usually do not exhibit cyanosis. However, when the pulmonary stenosis is severe, significant right-to-left shunting occurs, and clinically apparent cyanosis becomes evident. Cyanosis is commonly observed in areas rich in capillaries and superficial tissues, such as the lips, fingertips, nail beds, and bulbar conjunctiva.
Why does Tetralogy of Fallot squat?
The primary deformity in Tetralogy of Fallot is the obstruction of the right ventricular outflow, which leads to increased right ventricular pressure and a right-to-left shunt causing cyanosis. When the child squats, the flexion of the lower limbs can reduce the return of blood to the heart, alleviating the burden on the right ventricle. At the same time, it can increase systemic circulation resistance, reducing the right-to-left shunt in the heart, thereby alleviating the child's symptoms of hypoxia.
The reason for squatting in Tetralogy of Fallot
The reason for squatting is that when squatting, the lower limbs are bent, which reduces the amount of blood returning to the heart through the veins, thereby reducing the load on the heart. At the same time, the arteries in the lower limbs are compressed, which increases the resistance in the systemic circulation and reduces the right-to-left shunt volume, allowing temporary relief from hypoxia symptoms. Babies who cannot walk often like to be held by adults in a position that bends the lower limbs to reduce the amount of blood returning to the heart. This frequently occurs during walking and playing, often characterized by brief periods of squatting.
Tetralogy of Fallot's composition and its causes of formation
Tetralogy of Fallot consists of four abnormalities. First, there is a narrowing at the right ventricular outflow, ranging from the entrance of the right ventricular infundibulum to the branches of the left and right pulmonary arteries. Second, there is a ventricular septal defect, characterized by a deficiency around the membranous part that extends towards the outflow. Third, the aorta overrides, where the base of the aorta is enlarged and rotates clockwise to the right, straddling the septal defect. Fourth, right ventricular hypertrophy, which is a secondary lesion.
Tetralogy of Fallot Clinical Characteristics
Tetralogy of Fallot is the most common cyanotic congenital heart disease in infancy, accounting for about 12% of all congenital heart diseases. It is caused by malformations of four heart structures: 1. right ventricular outflow tract obstruction; 2. ventricular septal defect; 3. overriding aorta; 4. right ventricular hypertrophy. Its clinical manifestations may include cyanosis, squatting symptoms, clubbed fingers, and paroxysmal hypoxia attacks. Physical examinations generally show delayed development, a prominent precordial area, and at the second to fourth rib interspace along the left sternal margin, a grade 2 to 3 rough systolic murmur can be heard.
Emergency treatment for cyanosis in Tetralogy of Fallot
During hypoxic attacks of Tetralogy of Fallot, for mild cases, adopting the knee-chest position can provide relief. Severe cases should immediately receive oxygen and be given relevant medication treatment. Normally, attention should be paid to removing factors that cause hypoxic attacks, such as anemia and infections, and keep the child as calm as possible. For cases where hypoxia cannot be effectively controlled through the above measures, emergency surgical repair should be considered.
Tetralogy of Fallot seizure causes
The cause of seizures in Tetralogy of Fallot is episodic hypoxia leading to cerebral hypoxia, which causes seizures, commonly seen in infants. These seizures can be triggered by feeding, crying, emotional excitement, anemia, or infections, manifesting as episodic breathing difficulties. In severe cases, sudden fainting, convulsions, or even death may occur. The underlying cause is the narrowing of the pulmonary artery infundibulum and sudden muscle spasms, which lead to temporary pulmonary artery obstruction, worsening cerebral hypoxia.
Tetralogy of Fallot in children who prefer squatting is because
Tetralogy of Fallot exhibits squatting symptoms because squatting involves flexing the lower limbs, which reduces the amount of venous return to the heart, thereby decreasing the cardiac workload. At the same time, the arteries of the lower limbs are compressed, increasing systemic vascular resistance, reducing right-to-left shunting, and temporarily alleviating hypoxia symptoms. Infants who cannot walk often prefer to be held with their thighs up, with both lower limbs bent; after they become able to walk, they frequently squat down momentarily during walking or playing.