Tetralogy of Fallot

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Read about Tetralogy of Fallot, a condition involving four congenital defects that occur when the heart does not develop normally.

Key points

  • With Tetralogy of Fallot, a hole in the lower chambers of the heart results in the body receiving less oxygen than normal.
  • Symptoms include a murmur and sometimes a blue spell.
  • Surgical repair of this defect is usually very successful.

Tetralogy of Fallot is a condition of several congenital defects that occur when the heart does not develop normally. "Tetra" is the Greek word for four, meaning that the condition involves four defects, although it is primarily influenced by two major defects.

Normal heartNormal heart showing placement of the atria, ventricles, aorta, superior vena cava, inferior vena cava, pulmonary artery and pulmonary veins
The heart has two upper (receiving) and two lower (pumping) chambers. Blood flows into the upper chambers (the right atrium and the left atrium). The lower chambers (the right and left ventricles) pump blood out of the heart. The heart valves open and close to keep blood flowing in the correct direction.
Tetralogy of FallotHeart with thickened and narrowed pulmonary valve, thickened right ventricle, misaligned aorta and a hole between the left and right ventricles
Tetralogy of Fallot is a condition where there is a ventricular septal defect and an obstruction to the passage of the blood from the right ventricle to the pulmonary artery. This obstruction can occur in the area below the pulmonary valve, at the valve, or above the valve. If the obstruction is severe, it can result in less blood flow to the lungs, and blood low in oxygen to be pumped to the body.

Tetralogy of Fallot accounts for 3.5% to 9% of heart defects.

This condition involves a ventricular septal defect and pulmonary stenosis. The pulmonary valve may also be small. The other two components are a thickened right ventricle wall and an aorta that is shifted towards the right side of the heart, over the ventricular septal defect. There is sometimes a patent ductus arteriosus through which blood flows from the aorta to the pulmonary arteries.

What are the symptoms of Tetralogy of Fallot?

Symptoms include a murmur. Sometimes, children experience a blue spell.

Tetralogy of Fallot is diagnosed by way of a chest X-ray, an electrocardiogram, and an echocardiogram. Rarely, cardiac catheterization may be needed to confirm the anatomy prior to surgery.

Treatment of Tetralogy of Fallot

If the baby has had a blue spell, medications can help prevent further spells. Surgery will be needed, though not usually right after birth. This may involve putting in a shunt to help blood flow through the pulmonary arteries and closing the ventricular septal defect, or a complete repair.

What are the outcomes of treatment for children with Tetralogy of Fallot?

Repair of this defect is usually very successful. However, in some cases there may be a leaky pulmonary valve. This can take its toll on the right ventricle, and may require a valve replacement. In some cases, the pulmonary valve can narrow over time, requiring more surgery. Heart rhythm problems (arrhythmias)​ are also a potential risk.

Last updated: December 4th 2009