Tetralogy Of Fallot: Causes, Symptoms, And Treatment

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Tetralogy of Fallot is the infrequent condition that is caused by an amalgamation of four heart defects that are congenital (present at the birth). This imperfection affects the heart structure and might cause insufficiency of oxygen in the blood to flow of the heart. The children that have tetralogy of Fallot have blue-tinged skin because of the insufficiency of oxygen in the blood. This condition is frequently diagnosed in infancy, while this may not be recognized until in life. The diagnosis of this condition depends on the severity of the defects. 

What are the causes of the Tetralogy of Fallot?

This congenital heart defect occurs at the time of fetal growth when the heart of babies starts to develop. Usually, the etiology of this condition is not known. Still, the Tetralogy of Fallot is the cardiac condition that is the combination of four heart defects because of the insufficiency of oxygen in the blood or the rest of your body. These four defects are,

1. Ventricular septal defect:- 

Ventricular septal defect (VSD) is the condition in which abnormal holes present in the heart (between the right and left pumping chambers) that separate lower chambers of the heart. This condition permits the oxygen-poor and oxygen-rich blood mix together (means the deoxygenated blood enters the right ventricle and then flows in the left ventricle to mix with the pure oxygenated blood). Then after a while, the blood of the left ventricle again returns to the right ventricle in ineffective manners. 

This may cause VSD that lowers the supply of oxygenated blood to the rest of the body and weakens or incapacitates the heart.

2. Overriding of the aorta:- 

Overriding of the aorta is the congenital disability of the heart where the aortic valve becomes enlarged, and it arises from the left and right ventricles (over a VSD), rather than left ventricular that is considered as a normal heart. Because of this overriding, aorta gets the blood from both ventricles (right and left) and amalgamates the left ventricle with poor oxygen with left ventricle rich oxygen.

3. Pulmonary Stenosis:- 

Pulmonary stenosis is also known as pulmonic stenosis defect. It is the defect in which the valve that is present between the right ventricle and pulmonary artery becomes narrow or stiff, and it may create an obstruction or blockage of the flow of blood. This constriction of pulmonary valves lowers the flow of blood to the lungs.

4. Right ventricular Hypertrophy- 

RVH is the condition of the heart in which abnormal enlargement of the right ventricle occurs due to an overload of pressure (the right ventricle pumps the blood at high pressure).

These are the four defects of the heart that cause the tetralogy of Fallot. Still, few percents of the children have additional weaknesses due to the abnormalities of the pattern of coronary arteries. This condition is also referred to as chromosomal abnormalities and complete blockage of flow from the right ventricle.

What are the symptoms of Tetralogy of Fallot?

The indication, sign or symptoms of tetralogy of Fallot may vary, and it depends on its severity and the blockage or obstruction of the flow of blood, but the foremost sign and symptom of this congenital conditions may include, 

  • Cyanosis: (Bluish color of the skin due to insufficiency of oxygen in the blood that flows in rest of the body)
  • Dyspneic: (Shortage of the breath especially during the exercise or feeding that disturbs daily life)
  • Fainting: (Loss of consciousness because of inadequate supply of oxygen to the brain)
  • Clubbing:  (End of finger and toes becomes enlarge and the nails also become rounded or curve because the poor supply of oxygen)
  • Weight loss: (Reduction of the body mass rapidly)
  • Tiring (Needs to rest during any activity)
  • Heart Murmur: (Whooshing or swing sound of the heart during heartbeat cycle)
  • Irritability
  • Crying

Risk Factor of Tetralogy of Fallot:-

As you know, the aetiology of this condition is not known, only the four defects of heart cause this condition in children that’s why lots of factors increase the risk of tetralogy of Fallot in babies that are born. These risk factors include,

  • Mother gets any viral illness such as rubella: (Referred to as German measles infection that is caused by rubella virus) at the time of pregnancy.
  • Alcoholism: (Consumption of alcohol at the time of pregnancy)
  • Age Factor: (Mother is over age such as they are 40 or 40+ during pregnancy)
  • Poor Nutrition: (Mother not taking proper diet means they are not getting enough nutrients and developed malnutrition condition at the time of pregnancy)
  • Parent with this congenital septal defect: (Tetralogy of Fallot)
  • Presence of Down syndrome: (Genetic disorder due to the presence of trisomy, third copy of chromosome 21)
  • Presence of DiGeorge syndrome: (Due to deletion of a small segment of chromosomes)

What are the complications your baby faced?

The complications that almost all babies face who have tetralogy of Fallot should need surgery because, without any corrective surgery or treatment, babies do not develop and grow properly. They have chances to increase the risk factors that develop serious conditions (like endocarditis- Infection of heart valve due to bacterial infections). 

If you don’t treat this congenital defect, then your baby faced lots of complications over a period of time that may result in death at adulthood or faced any disability.

How can you diagnose the tetralogy of Fallot?

If your doctor suspects you and your baby of the tetralogy of Fallot, it means they noticed cyanosis (blue-tinged skin) or any whooshing sounds that cause abnormal blood flow. Your doctor conducts a physical examination, and after examination, they recommended some tests before birth and after birth to confirm their diagnosis.  These tests are,

Before Birth:-

During your pregnancy or before the child was born, it is necessary that your doctor recommended some parental tests to evaluate any birth (congenital) defects. This congenital heart defect can be visualized with the help of ultrasound at the time of pregnancy. If the doctor may suspect that your child will be born with this tetralogy of Fallot, then they perform an echocardiogram to assess issues of heart structure. 

After Birth:-

After birth, you should concerned with your pediatric cardiologist that evaluate your baby’s heart and, pulses, lungs, and measure the oxygen level in blood by using some test, these are

  1. Electrocardiogram:- ECG records the electrical impulses of your heart each time when it contracts. The patches of electrodes (wires) are being placed on your baby’s chest, ankles, and the wrist then these electrodes compute the electrical activities of your baby’s heart that are recorded on the paper.  ECG helps to investigate the enlargement of the right ventricle that the right atrium is normal or there is any hypertrophy present.
  2. Echocardiography:- This is the high-pitch sound waves that produce images of the heart. This test helps your doctor to diagnose the tetralogy of Fallot that tells your doctor, is there any ventricular septal defect present or not? Is the pulmonary valve normal or not? Functioning of the right ventricular, and any heart defects present or not? Echocardiography also helps to make a plan of treatment for this condition.
  3. Measurement of Oxygen level:- For measuring oxygen level, a pulse oximeter is used, which is a small sensor that is placed on your baby’s finger to measure the level of oxygen in the blood.
  4. Chest X-ray:- Chest X-ray helps your doctor to recognize the heart and lung structure. The most common sign of this congenital defect that appears on X-ray is a boost shaped heart because of hypertrophy of the right ventricle.

Treatment of Tetralogy of Fallot:- 

Generally, there is no treatment present for the tetralogy of Fallot because of its structure abnormalities. Surgical correction is the only option to treat this condition. The ultimate goal of this initial surgery is to repair the defect. Some born babies may have developed leakage of in valves that needed to be replaced in the future. At the same time, the adults or teenagers with tetralogy of Fallot deals with follow-up, appointments, and with some physical restrictions. Children needed surgery to manage their complete repair. The few interventions required hospitalization, these are

Cardiac Catheterization:- 

Cardiac catheterization helps your doctor to assess the structure of your baby’s heart and make plans for surgery. In this procedure, a thin, flexible catheter inserted in arteries or vein and injected dye through this catheter helps to visualize the structure of the heart. Most babies do not need this cardiac catheterization that has tetralogy of Fallot, but sometimes this procedure is required to make a plan of treatment. This procedure also helps to measure the level of oxygen that is present in heart chambers and blood vessels.


Babies with tetralogy of  Fallot recommended surgery between three to six months. Rarely babies needed a stage to approach the operations or initial surgery. The shunt is placed between the heart and lung artery to enhance the flow of blood. The full surgical procedure of the tetralogy of Fallot consists of, Closing the septal defect between ventricles and relieving the constriction between the pulmonary artery and the right ventricle.

Are there any potential problems associated with tetralogy of Fallot?

Surgical correction is indeed proven very useful in the tetralogy of Fallot to correct the structure of the heart and defects of the heart. But as we all are aware, surgeries have their complications; this may also cause some abnormalities that affect heart function. If there is any problem occurring, then another surgery is needed to correct this function, but there is no 100% guarantee or surety. According to studies that are reported by Canadian adult heart networks, 10- 15% of people face complications, and they need to reoperate over 20 years. These potential problems are, 

  1. Electrical abnormalities:- During surgery, placing a patch on the ventricular defect might be blocking the atria’s ability to transmit the signal of ventricles. The pacemaker corrects this blockage. 
  2. Leakage of Valves:- The valves of the heart is designed that allows the blood to flow in one direction.  But when there is leakage of the pipe, the blood returns to the chambers. The patient who was treated with surgery has developed the risk of this leakage because this is the most common complication of leaking pulmonary valve and tricuspid valve. 
  3. Rhythm Disturbance:- Arrhythmia is also the common problem of heart surgery in which your heart is pumping irregularly and quickly. This may also become life-threatening if it is not treated appropriately. 
  4. Aneurysm:– The patches appeared on the ventricle; that’s why there are chances of increasing aneurysms that cause weakening of ventricles. 


TOF is a rare condition that is developed in babies with four separate heart defects. This congenital heart may develop due to septal defects, pulmonary hypertrophy, overriding of the aorta, and pulmonary stenosis. This condition may develop during pregnancy because of poor nutrition, intake of alcoholism, or presence of the down syndrome. The patient with diseases appears with the symptom of cyanosis because of the insufficiency of oxygen in the blood and the rest of the body. The initial approach to treat this condition is surgery to close the septal defects. There are also numerous potential complications associated with TOF, such as valves leakage and arrhythmias.