Tetralogy of Fallot

Tetralogy of Fallot (te-TRAL-uh-gee of fal-LOH) is a group of four heart defects present at birth. These defects change the flow of blood through the heart and cause a low level of oxygen in the blood. Tetralogy of Fallot affects both boys and girls of all ethnic backgrounds. It occurs in about 5 of every 10,000 babies born. It is not known what causes tetralogy of Fallot to develop in a baby before birth.

The four heart defects present in tetralogy of Fallot are:

• Ventricular septal defect – a hole in the wall of muscle between the right and left sides of the heart
• Pulmonary valve stenosis – narrowing of the entrance to the large blood vessels that carry blood from the heart to the lungs
• Overriding aorta – the large blood vessel (aorta) that carries blood out of the heart to the body doesn’t start in the right place. The aorta should begin in the left side of the heart (in the left ventricle), but in tetralogy of Fallot it begins in the middle of the heart right over the hole between the two sides (the ventricular septal defect)
• Right ventricular hypertrophy – the three other heart defects cause the right side of the heart to work extra hard. The heart muscle on that side gets bigger because of this.

In a healthy heart, blood is pumped out of the heart through the pulmonary artery to the lungs to get oxygen. It then comes back to the heart and is pumped out through the aorta to the body. In tetralogy of Fallot, because of the four heart defects the blood that is pumped out to the body is low in oxygen.

Symptoms

Babies born with tetralogy of Fallot usually have symptoms that include:

• cyanosis – a bluish tint to the skin, lips, and fingernails
• periods of severe cyanosis – the baby may turn a dark blue color during increased activity such as crying or having a bowel movement – this is called a hypercyanotic episode or “tet spell”
• heart murmur – the heart defects in tetralogy of Fallot change the flow of blood in the heart. A doctor can hear the sounds of this abnormal blood flow using a stethoscope
• difficulty feeding – the baby becomes tired easily when feeding and may not be able to take in enough calories. A baby with tetralogy of Fallot may not gain weight as fast or grow as quickly as babies with healthy hearts.
• clubbing of fingertips – children may have an abnormal rounded shape to their fingertips due to low oxygen levels in the blood

Diagnosis

The diagnosis of tetralogy of Fallot is based on the symptoms present such as cyanosis or difficulty feeding. An ultrasound of the heart (echocardiogram) is done to look at the heart. The doctor can see the heart defects and confirm the diagnosis.

Treatment

The heart defects in tetralogy of Fallot must be repaired with open-heart surgery. The heart surgeon will close up the hole (the ventricular septal defect) in the heart and widen the pulmonary stenosis. In the past, a temporary surgery was done during infancy to improve blood flow in the heart, and the complete repair was done in childhood. Now most babies with tetralogy of Fallot have the complete repair done in infancy.

A child with tetralogy of Fallot will be cared for by a children’s heart specialist, called a pediatric cardiologist. Even after the surgery, the child will continue to see the cardiologist for regular heart checkups. Some teenagers or young adults who had tetralogy of Fallot repair as babies may need additional heart surgery as they grow older because of complications that can develop.

_Source:

"What Is Tetralogy of Fallot?." Diseases and Conditions Index. National Heart Lung and Blood Institute. 24 Oct 2008