What Are the Signs and Symptoms of Tetralogy of Fallot?

An important symptom of tetralogy of Fallot is cyanosis, or a bluish tint to the skin, lips, and fingernails. Low levels of blood in the oxygen cause this symptom.

Babies with tetralogy of Fallot sometimes have “tet spells" in response to an activity like crying or having a bowel movement. A “tet spell” occurs when the oxygen level in the blood suddenly drops. This causes the baby to become very blue. The baby may also:

• Have a hard time breathing
• Become very tired and limp
• Not respond to a parent’s voice or touch
• Become very fussy
• Lose consciousness

In years past, when tetralogy of Fallot wasn’t treated in infancy, children would get very tired during exercise and could have fainting spells. This heart defect is now repaired in infancy to prevent these "tet spells".

Another common symptom of tetralogy of Fallot is a heart murmur. A heart murmur is an extra or unusual sound that a doctor can hear while listening to the heart during a physical exam. When a heart defect causes an abnormal flow of blood through the heart, it will make a certain sound. However, not all murmurs are signs of congenital heart defects. Many healthy children have heart murmurs.

Normal growth and development depend on a normal workload for the heart and normal flow of oxygen-rich blood to all parts of the body. Babies who have tetralogy of Fallot may not gain weight or grow as quickly as children with healthy hearts because they tire easily while feeding.  Children with this congenital heart defect also may have “clubbing,” an abnormal, rounded shape to the skin or bone around the fingernails felt to be secondary to low oxygen levels in the bloodstream.