Tetralogy of Fallot is a complex heart defect in which blood pumped to the body is lacking in oxygen, sometimes resulting in the skin taking a blue tone. There are four components to the condition involving various parts of the heart. People are born with this condition, or develop it soon after birth. Most children diagnosed with this condition have open-heart surgery before school age. Some infants with tetralogy of Fallot may need an operation to allow for increased circulation of oxygenated blood. Lifelong medical follow-up is needed.