Tetralogy Of Fallot

Dr. Ira Shah
Consultant Pediatrician, B.J.Wadia Hospital for Children, Mumbai, India
First Created: 01/08/2001  Last Updated: 01/08/2001

Patient Education

What is Tetralogy of Fallot (TOF)?

The heart consists of 4 chambers, the right atrium that receives oxygen-poor blood from the body, the right ventricle that receives blood from the right atrium and pumps it through the pulmonary artery to the lungs to get oxygen; the left atrium that receives oxygen-rich blood from the lungs and left ventricle that receives blood from the left atrium and then pumps it through the aorta to the rest of the body. In Tetralogy of Fallot, there is a large hole between the two ventricles (ventricular septal defect) that lets blood pass from the right to the left ventricle without going through the lungs along with a narrowing near the outflow of the right ventricle thus restricting blood flow into the pulmonary artery. In addition, since the right ventricle has to pump blood against a narrowing, it is more muscular. Also, the aorta opens directly over the ventricular septal defect.

What happens in Tetralogy of Fallot?

Since there is a mixing of both oxygen-poor blood and oxygen-rich blood in the left ventricle which goes into the body, there is a bluish color of the baby (due to less oxygen in the blood). These babies have sudden episodes of the increased bluish color of the body along with rapid breathing and may even become unconscious. These episodes are known as cyanotic spells. Cyanotic spells are more open after 6 months of age and can occur at an increased frequency.

What are the causes of Tetrology of Fallot(cyanotic spells)?

There is a "spasm" of the band of muscles just at the right ventricle narrowing. This leads to a further decrease in blood flowing into the lungs and thus increased blue color as the oxygen content of blood becomes very low. To compensate this, the patients breathe rapidly and try and take in as much oxygen into the lungs as possible.

There are several provoking factors that can precipitate cyanotic spell such as exercise, fever, diarrhea, dehydration, etc. To compensate for these spells, children tend to squat to decrease blood supply to the right ventricle and thus decreasing the right to left shunting of blood. Sometimes these spells may be life-threatening.

What is the treatment of Tetralogy of Fallot?

Some infants with severe Tetralogy of Fallot may need an operation to increase blood supply to the lungs. This is done by shunt surgery whereby the connection between the aorta and pulmonary artery is made. This increases the oxygen content of the blood. In older children, corrective surgery is required which involves closing the ventricular septal defect, removing the muscle causing narrowing in the right ventricular outflow.

What happens if a patient with Tetralogy of Fallot does not undergo surgery?

If a patient with Tetralogy of Fallot does not undergo surgery, there is an increased risk of stroke, brain abscess, heart failure. Sometimes a cyanotic spell may be fatal. Over a period of time, due to constant decreased oxygen supply to the heart and other organs of the body, the heart becomes weak.

What is the prognosis post surgery?

After surgery, long term outlook varies depending on how severe the defects were before surgery. Lifelong follow up with cardiologist is needed.


Tetralogy of Fallot Tetralogy of Fallot Tetralogy of Fallot 08/01/2015
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