Tetralogy of Fallot

Tetralogy of Fallot (teh-tral-uh-je ov fuh-LOE) is a rare condition caused by a combination of four heart defects that are present at birth. These defects, which affect the structure of the heart, cause oxygen-poor blood to flow out of the heart and into the rest of the body. Infants and children with tetralogy of Fallot usually have blue-tinged skin because their blood doesn't carry enough oxygen.

Tetralogy of Fallot is often diagnosed during infancy or soon after. However, tetralogy of Fallot may not be detected until later in life, depending on the severity of the defects and symptoms. With early diagnosis followed by appropriate treatment, most children with tetralogy of Fallot live relatively normal lives, though they'll need regular medical care and may have restrictions on exercise.

Symptoms Causes Risk factors Complications

Tetralogy of Fallot symptoms vary, depending on the extent of obstruction of blood flow out of the right ventricle and into the lungs. Signs and symptoms may include:

  • A bluish coloration of the skin caused by blood low in oxygen (cyanosis)
  • Shortness of breath and rapid breathing, especially during feeding
  • Loss of consciousness (fainting)
  • Clubbing of fingers and toes — an abnormal, rounded shape of the nail bed
  • Poor weight gain
  • Tiring easily during play
  • Irritability
  • Prolonged crying
  • A heart murmur

Tet spells

Sometimes, babies with tetralogy of Fallot will suddenly develop deep blue skin, nails and lips after crying, feeding, having a bowel movement, or kicking his or her legs upon awakening. These episodes are called Tet spells and are caused by a rapid drop in the amount of oxygen in the blood. Toddlers or older children may instinctively squat when they are short of breath. Squatting increases blood flow to the lungs. Tet spells are more common in young infants, around 2 to 4 months old.

When to see a doctor

Seek medical help if you notice that your baby has the following symptoms:

  • Difficulty breathing
  • Bluish discoloration of the skin
  • Passing out or seizures
  • Weakness
  • Unusual irritability

If your baby becomes blue (cyanotic), immediately place your child on his or her side and pull the knees up to the chest. This helps increase blood flow to the lungs. Call 911 or your local emergency number immediately.

© 1998-2015 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. Terms of use