Tetralogy Of Fallot

1 What is Tetralogy of Fallot?

Tetralogy of Fallot is a congenital condition that consists of four abnormalities in the structure of the heart and the vessels that leave the heart.  The abnormalities include: pulmonary stenosis (abnormal narrowing), right ventricular hypertrophy ( thickening), ventricual setal defect (VSD) and coartation of the aorta ( misplaced aorta). 

The presence of a defect within the ventricular septum causes deoxygenated  blood from the right to mix with oxygenated blood in the left part of the heart. Usually not all but three of these defects are present. 

This results in a decreased supply of xygenated blood to the tissues of the body. The only effective treatment is surgery to correct the pulmonary stenosis and ventricular septal defect.

2 Symptoms

The sign and symptoms of Tetralogy of Fallot include:

  • bluish discoloration of the skin,
  • shortness of breath and rapid breathing especially during stressful activities like running,
  • poor weght gain,
  • clubbing of fingers and toes ( abnormal rounded shape of the nail bed) ,
  • heart murmurs and loss of conciousness. 

Test spells are usually seen in babies. They are episodes that are accompanied by a sudden development of bluish discoloration of the skin, nails or lips after crying or feeding or when the baby is agitated. This is caused by a drop in the levels of oxygen in the blood. 

They are more common in in babies who are 2-4 months old. Toddlers with tetralogy of Fallot usually squat when they are out of breath since this increases blood flow to the lungs.

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3 Causes

 Although the exact cause of tetralogy of Fallot is unknown, certain environmental factors can increase the chances of a baby being born with tetralogy of Fallot. These factors include:

  • smoking,
  • consuming alcohol,
  • having rubella during pregnacy.

Genetic factors can have also been shown to cause this disease.

4 Making a Diagnosis

If tetralogy of Fallot is suspected by a bluish skin discoloration the following examinations can be carried out to make a diagnosis:                                                                                                                                                                                       

  • auscultation  in which  a sthethoscope is used to check for heart murmurs                                                         
  • echocardiography in which sound waves are used to produce images of the heart which can be viewed on a screen. It allows doctors to find the exact location of the ventricular septal defect                               
  • electrocardiogram (ECG)- electrodes are placed on the chest to determine the electrical activity of the heart. The electrical activity of the heart is recorded on a paper. This test helps to check the presence of an enlarged right ventricle.                                                                                                                                     
  • Simple x-ray of the chest-to check the shape of the heart and lung. The heart of a baby with tetralogy of Fallot usually appears boot shaped because of an enlarged right ventricle                                       
  • cardiac catheterization in which a thin flexible tube is inserted into an artery or vein of a baby's arm or groin and goes  to the heart. A dye is then injected into the tube so that the structure of the heart can be viewed on an x-ray. This helps doctors to eveluate the structure of the heart and plan surgical treatment.                                                                                                                                                                  

Measurement of the levels of oxygen in blood using a small sensor that is placed on the fingers of toes of the paper.

5 Treatment

The only effective treatment for tetralogy of Fallot is surgery. Two types of surgical procedures are available:

  • intracrdiac repair
  • a temporary procedure in which a shunt is used. 

In intracardiac repair a patch is placed over the ventricalar septal defect to the hole in the septal wall. The pulmonary valve is also repaired or replaced to enable enough blood flow to the lungs. This procedure is usually performed after the child's first year of life. 

Temporary sugery is performed if the child is premature or has underdeveloped pulomany arteries. A shunt (bypass) is created between the large artery branching from the aorta and the pulmonary artery to imrove blood flow to the lungs. 

Usually intracardiac repair follows this procedure as a permanent treatment.  The common complications that are associated with intracardiac repair include:   

  • chronic pulmonary regurgitation, in which blood in the pulmonary artery flows back into the haert instead of flowing to the lungs                                                     
  • development of arrhythmians (irregular heartbeats)                                                                         
  • dilation of the aorta                                                                                                                               

Another risk of surgery is infection. Some children require more than one surery especially if complications arise.

6 Lifestyle and Coping

One can lead a normal lifestyle after the treatment of tetralogy of Fallot.

After surgery, it is important for the child to be monitored to prevent infections. Antibiotics are usually given for the prevention of infections that are connected with surgical procedures. After treatment, most children are usually capable of participating in different kinds of activities and can lead a normal life. 

Adults with tetralogy of Fallot can also lead normal lives. They able to perform a wide range of jobs even though they might not be encouraged to partake in competitive sport activities. Women who have repaired of tetralogy of Fallot are able to conceive although they must be carefully observed to prevent complications that can arise as a result of pulmonary regurgitation or cardiac arrythmias.

7 Risks and Complications

The following factors  can increase the risks of a baby being born with tetralogy of Fallot:

  • consuming alcohol during pregancy                     
  • poor nutrition during pregnacy                                  
  • pregancy in women who are older than 40                                                                                
  • having parents with tetralogy of Fallot                                        
  • having Down's syndrome or DiGeorge syndrome                                                                             

The complications associated with tetralogy of Fallot include:  an increased risk of developing infective endocarditis- in which there is inflammation of the inner lining of the heart, disabilities during early childhood and even death.

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