Tetralogy of Fallot

What is Tetralogy of Fallot?

Tetralogy of Fallot (TOF) is a congenital defect that hampers the normal flow of blood through the heart. This disease generally occurs in a baby whose heart does not develop properly while still in the womb. The defects generally affect the structure of the heart so much that they begin to cause oxygen-poor blood flow to the parts of the body. Infants who are suffering from tetralogy of Fallot have a tinge of blue in their skin colour and have an absolute restriction of blood flow from the right ventricle.

The condition, tetralogy of Fallot is also known to be associated with chromosomal abnormalities. When the flow of blood towards the lungs is limited, the fusion of the ventricular septal defect and aortic paves way for the passage of oxygen-poor blood coming back to the right atrium and the right ventricle.


The disease tetralogy of Fallot has symptoms that differ based on the degree of blockage of the flow of blood out of the right ventricle and into lungs. The major symptoms of the disease are:

  • Cyanosis: It is defined as a bluish tint on the lips, fingernails, and the skin.
  • Untimely tet spells in babies that turns their skin into a deep blue colour.
  • Problematic breathing.
  • Becoming limp and tired easily.
  • Not responding to touch or parent’s voice.
  • Becoming fussy.
  • Passing out frequently.
  • Heart murmur.
  • Prolonged cries.



The condition of tetralogy of Fallot occurs during fetal growth. Although, the exact cause is unknown, the four defects that lead to such condition are:

  • Pulmonary valve stenosis: Narrowing of the pulmonary valve.
  • Ventricular septal defect: A hole in the wall that separates the left and right ventricle.
  • Overriding aorta: The aorta shifts towards the right ventricle.
  • Right ventricular hypertrophy: Due to overworking of the heart while pumping, the muscular wall of the right ventricle thickens causing stiffness of the heart.



The main risk factors are:

  • Down syndrome.
  • Mother suffering from viral infection, such as rubella during pregnancy.
  • Consumption of alcohol during pregnancy.
  • Poor nutrition during pregnancy.
  • The mother’s age is above 40.
  • Any parent has tetralogy of Fallot.



As the possibility of the condition develops during pregnancy one should take care of certain points:

  • Avoid consumption of alcohol during pregnancy.
  • Maintain a healthy diet.
  • Get vaccination against various viral infections.

How is it diagnosed?

After a baby is born, the doctor might doubt if he/she has a tetralogy of Fallot by the kind of skin he/she has, and any unusual sound caused due to a heart murmur. A physical examination shall be ...

How is it treated?

For a disease like tetralogy of Fallot, surgery is always going to work effectively in curbing it. At Medanta, our doctors carry out the following surgical procedures:


  • Intracardiac repair

    It is an open-heart surgery, which is carried out on a baby in the first year of his birth. After the surgery is done on the baby, the level of oxygen in the blood comes to an increase, and the symptoms in the child shall begin to retire.

  • Temporary surgery

    It is a pre-surgery to intracardiac repair. The pre surgery is done to fulfill the purpose of increasing the flow of blood to the lungs. It is done by building a bypass between the large artery that comes from the pulmonary artery and aorta, so that the child is prepared for intracardiac repair without any complications.

When do I contact the doctor?

You need to consult a doctor, if you observe the symptoms of problematic breathing, easy tiring, or blue colouration of the skin. The doctor will conduct practical examination to find the correct defect, and carry forward the treatment.

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