Tetralogy Of Fallot (TOF)

Tetralogy Of Fallot
Body Parts: Chest Whole Body
Medical Subjects: Children's Health Heart Genetic disease

What Is Tetralogy Of Fallot?

Tetralogy of Fallot is a congenital heart disease and a common cardiac developmental deformity mainly including four cardiac malformations: right ventricular hypertrophy, ventricular septal defect, aortic saddle and right ventricular outflow tract obstruction (pulmonary artery stenosis), so it is called Tetralogy of Fallot.

Children with this disease will have blue lips, nails and skin when they are nursing, crying, emotional and cold. Generally, the symptoms are more obvious within 3–6 months after birth. Whether the condition is serious depends on the degree of right ventricular outflow tract obstruction.

In the absence of treatment, children generally die in early childhood, and very few patients can live to age 30. After surgical correction, most children can live normally.


What Is The Cause Of Tetralogy Of Fallot?

What causes tetralogy of Fallot?

Up to now, the causes of all congenital heart diseases including Tetralogy of Fallot are not completely clear, but it must be the result of the combination of genetic basis and teratogenic factors during pregnancy.

It has been observed that exposure to progesterone and estrogen during pregnancy increases the chances of developing Tetralogy of Fallot and excessive drinking during pregnancy also increases the risk of fetal malformations. In addition, babies with chromosomal abnormalities such as Down's syndrome and Noonan syndrome have a very high risk of Tetralogy of Fallot.

Is tetralogy of Fallot inherited?

The genetic factors of Tetralogy of Fallot are relatively small. According to research, only 10% of the genetic factors play a role. To avoid contact with toxic and harmful substances during pregnancy is the most important preventive measure.


What Is The Symptoms Of Tetralogy Of Fallot?

What is the blood circulation of the heart?

Heart blood circulation is divided into two parts: systemic circulation and pulmonary circulation:

  • Systemic circulation: Blood flows from the left ventricle to the aorta, through large and small arteries to the whole body, and through the capillaries to supply blood to various organs and tissues throughout the body, then back to the right atrium of the heart through the veins. Pulmonary circulation begins when blood from the right atrium flows into the right ventricle.
  • Pulmonary circulation: Blood flows from the right ventricle to the pulmonary artery, through large and small arteries in the lung to the pulmonary alveoli, where it exchanges gas and then flows back to the left atrium through the veins. The left atrial blood, into the left ventricle, and began to systemic circulation.

What will happen to a child with Tetralogy of Fallot after birth?

In a child with Tetralogy of Fallot, the severity of the condition depends primarily on the severity of the right ventricular outflow tract obstruction (pulmonary stenosis) of the four malformations. The blood in the right ventricle cannot flow smoothly to the lungs and normal gas exchange cannot be carried out. There is insufficient oxygen in the blood and a series of hypoxia symptoms will appear. Manifested as:

  • Cyanosis: the most obvious symptom in neonates and infants. The child of serious illness, can discover to eat milk soon after be born, cry when, the place with relatively rich capillary such as lip, fingernail appears cyanosis. For children with mild illness, symptoms may appear only 3–6 months after birth.

  • Squatting: This is the most typical and unique manifestation of Tetralogy of Fallot. Children with Tetralogy of Fallot may suddenly squat down when moving and walking. They can only move and walk normally after a while. This is because the activity of oxygen consumption is larger, children will appear hypoxia, and squat down to reduce the burden on the heart, improve the hypoxia.

  • Clubbed finger (toe): Due to lack of oxygen, capillaries proliferate in toe and finger areas where blood supply is easy to be insufficient. At the same time, bones and soft tissues in these areas may proliferate, leading to the enlargement of the joint area between fingernails and fingers, like the wooden stick hammering. This condition generally occurs in older pediatric and adult patients.

  • Paroxysmal hypoxia: it is relatively common in infants. due to nursing, crying and emotional excitement, dyspnea and even convulsion and syncope may appear in severe cases. it may even cause death due to hypoxia. this is because the already narrow pulmonary artery has spasm again. the stenosis is more serious and obstruction occurs, resulting in serious shortage of oxygen supply to the brain. In older children, paroxysmal hypoxia is less severe than in infancy and is dominated by paroxysmal dizziness and headache.


How To Check Tetralogy Of Fallot?

What should you check for Tetralogy of Fallot?

  • Heart auscultation: In general hospitals, after the child is born, doctors will examine the child and conduct heart auscultation. In children with tetralogy of fallot there is a heart murmur at auscultation because of abnormalities in the structure of the heart.

  • Echocardiography: Echocardiography can directly observe the structures of heart and large vessels, and is the most important examination method for diagnosing tetralogy of fallot. If the doctor finds a heart murmur during auscultation, or if the child suffers from repeated cyanosis and dyspnea, an echocardiogram can be taken to confirm the diagnosis of tetralogy of fallot or other congenital heart diseases.

  • X-ray examination: X-ray examination showed abnormal heart morphology and decreased blood vessels in the lungs of the children.

  • Cardiac catheterization: It is mainly used to determine the nature and degree of tetralogy of fallot deformity and whether there are other malformations, mainly for children undergoing surgical treatment and to guide doctors to formulate surgical plans.


How To Prevent Tetralogy Of Fallot?

If the first child has tetralogy of Fallot, is there any way to avoid it when giving birth again?

At present, the causes of Tetralogy of Fallot and other congenital heart diseases are still unclear and are generally considered to be the common result of genetic and harmful factors during pregnancy. Exposure to progesterone and estrogen during pregnancy increases your baby's chances of developing Tetralogy of Fallot and excessive drinking during pregnancy also increases the risk of fetal malformations.

Since the role of genetic factors is unknown (studies have said that only 10% of the causes of congenital heart diseases are inherited), avoiding exposure to various toxic and harmful substances is the most realistic way to reduce the incidence of heart malformations in children.

If you give birth to a baby with tetralogy of fallot, you should avoid contact with a variety of toxic and harmful substances during pregnancy, and conduct antenatal examination on time. Fetal deformity screening should be conducted during the 20–24 weeks of pregnancy. In addition, it is also possible to conduct a special ultrasound examination for the fetal heart, the "fetal echocardiography", which can detect heart malformations such as Tetralogy of Fallot at around 20–22 weeks of gestation.


How To Treat Tetralogy Of Fallot?

Which department treats tetralogy of fallot?

Treatment is generally performed by cardiac (or cardiothoracic) surgery. If conditions permit, cardiac surgery or neonatal surgery at a children's hospital is more appropriate.

During pregnancy, if the fetus is diagnosed with Tetralogy of Fallot, should you give up the child?

Most tetralogy of fallot can be diagnosed by screening for malformations at 20 to 24 weeks of gestation, in addition to fetal echocardiography.

Most patients with tetralogy of fallot can live normally after surgical treatment. If the fetus is found to have tetralogy of fallot during pregnancy, it is not medically necessary to abandon the child. However, we must also consider the family's ability to bear it. We must analyze the specific situation and cannot give a definite answer.

How to treat tetralogy of fallot?

Surgical treatment is the most important treatment for tetralogy of fallot.

When conditions permit, radical cardiac repair is usually performed to correct heart malformations, restore normal systemic and pulmonary circulation, and improve hypoxia. Treatment was previously thought to be in childhood, but is now thought to be performed within one year of age (most around half a year).

If the physical condition of the child does not allow it, palliative shunt can be performed first, that is, shunt is caused between systemic circulation and pulmonary circulation to temporarily increase blood flow in the lungs, so that the child can survive and an opportunity for intracardiac repair is obtained.

Is surgical treatment of tetralogy of fallot risky?

Any treatment will be risky. Surgical treatment for Tetralogy of Fallot also has the same anesthesia risks, postoperative bleeding, and cardiac arrest as other operations.

However, the surgical technique for tetralogy of fallot is now relatively mature, and few children die due to the operation. However, surgical treatment is very important for the children's normal life in the future.

In general, the benefits from surgical treatment far outweigh the risks when surgical conditions are available. As a parent, follow the doctor's instructions to prepare for the surgery.

Will treatment of tetralogy of fallot lead to other diseases?

Children with tetralogy of fallot are at risk of long-term postoperative complications after cardiac repair, including pulmonary valve insufficiency, right ventricular insufficiency, aortic root dilatation and aortic valve insufficiency, arrhythmia, etc. These examinations can be found timely through long-term follow-up and physical examination after operation, and can be corrected with mature treatment.

In addition, the risk of sudden cardiac death after surgery for tetralogy of fallot is higher than in other populations. The main reason is malignant arrhythmia. Active follow-up and physical examination after operation can identify some high-risk factors leading to sudden cardiac death and take timely measures to avoid the occurrence of some sudden cardiac death.

Do you need to review after treatment for Tetralogy of Fallot?

Need to review. Cardiac reexamination mainly includes:

  • Color Dopplar ultrasound of the heart, once a year before the age of 10, and once every two years after the age of 10.
  • ECG, once a year.
  • 24 hours dynamic electrocardiogram, generally every 3 ~ 4 years.
  • Cardiac magnetic resonance imaging, mainly for adults, can be examined once every 2 to 4 years.
  • In addition, there are exercise tests, cardiac catheterization, cardiac electrophysiology, and so on, to be carried out according to the situation of different patients.
  • In addition, hypoxia in tetralogy of fallot before treatment may affect the development of nervous system, and parents should pay attention to the evaluation of neurodevelopment and timely rehabilitation treatment.


What Should Patients With Tetralogy Of Fallot Pay Attention To In Life?

Can a treated child with Tetralogy of Fallot go to school and take care of himself?

The vast majority of children can go to school and live normally after treatment, just like other children. As long as the patients were reexamined regularly according to the doctor's requirements after treatment, and the problems were found, they were dealt with in time, and there was no special need to be noticed.

In addition, hypoxia before treatment may affect the child's neurodevelopment, attention should be paid to neurodevelopmental evaluation, and timely rehabilitation treatment.

Can children with tetralogy of Fallot who have been treated be able to participate in sports activities?

After the treatment, if the child's heart function is normal and there is no arrhythmia, physical activities, including various competitive sports, can be performed.

Can women with tetralogy of Fallot have children?

Fertility is not recommended in women with tetralogy of fallot without treatment. In a treated patient with tetralogy of fallot, a thorough evaluation by a cardiologist should be performed before giving birth to determine that the physical condition is tolerable. During pregnancy, the risk of arrhythmia and heart failure is higher than that of the average pregnant and lying-in women. We should pay attention to the delivery inspection on time. In addition, the risk of fetal chromosomal abnormalities and heart abnormalities is higher than others, so screening for chromosomal abnormalities and fetal heart abnormalities should be conducted during pregnancy.

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