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Tetralogy of Fallot Symptoms Treatment

Tetralogy of Fallot is a serious and complex heart defect which involves four specific defects:

  • A large ventricular septal defect (VSD)
  • Pulmonary valve stenosis
  • Right ventricular hypertrophy
  • Overriding aorta
Ventricular Septal Defect

A VSD is a hole in the part of the septum that separates the ventricles—the lower chambers of the heart. The hole allows oxygen‑rich blood to flow from the left ventricle into the right ventricle instead of flowing into the aorta, the main artery leading out to the body.

Pulmonary Stenosis

This is a narrowing of the pulmonary valve and the passageway through which blood flows from the right ventricle to the pulmonary arteries. Normally, oxygen-poor blood from the right ventricle flows through the pulmonary valve into the pulmonary arteries and out to the lungs to pick up oxygen. In pulmonary stenosis, the heart has to work harder than normal to pump blood, and not enough blood can get to the lungs.

Right Ventricular Hypertrophy

This is when the right ventricle thickens because the heart has to pump harder than it should to move blood through the narrowed pulmonary valve.

Overriding Aorta

This is a defect in the location of the aorta. In a healthy heart, the aorta is attached to the left ventricle, allowing only oxygen-rich blood to go to the body. In tetralogy of Fallot, the aorta is between the left and right ventricles, directly over the VSD. As a result, oxygen‑poor blood from the right ventricle can flow directly into the aorta instead of into the pulmonary artery to the lungs.

Tetralogy of Fallot

Figure A shows the normal anatomy and blood flow of the interior of the heart. Figure B shows a heart with the four defects of tetralogy of Fallot.

These four defects mean that not enough blood is able to reach the lungs to get oxygen, and oxygen-poor blood flows out to the body. When the oxygen level in the blood is below normal, the baby's skin, fingertips, or lips have a bluish tint. This condition is called cyanosis. An infant with cyanosis is sometimes called a "blue baby." This rare and complex heart defect occurs in about 5 out every 10,000 babies. It affects boys and girls equally.

Tetralogy of Fallot must be repaired with open‑heart surgery, either soon after birth or later in infancy. The timing of the surgery depends on how severely the pulmonary valve is narrowed. Over the past few decades, the diagnosis and treatment of tetralogy of Fallot has greatly improved. As a result, the majority of children with this heart defect grow to adulthood. However, they need lifelong medical care from a specialist to make sure they stay as healthy as possible.