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Clinical features

The age at which children with Tetralogy of Fallot present depends on the degree of pulmonary obstruction. If there is complete atresia then the child will present as a newborn baby with profound cyanosis. If there is adequate flow through the pulmonary circulation then the child will be pink in the newborn period. However, there will be an obvious murmur in the pulmonary area and as the child grows the subvalvar pulmonary stenosis tends to progress so that cyanosis usually occurs before the age of 1 year.

• Degree of and age of development of cyanosis depends on severity of pulmonary obstruction
• Commonly presents in neonates/infants with cyanosis
• Hypercyanotic spells + squatting after exertion rarely seen nowadays as most are repaired early

Hypercyanotic spells occur in children with Tetralogy of Fallot. They are rare in the newborn period but can happen in later infancy and childhood, especially after episodes of crying or exertion. They are due to the muscular right ventricular outflow tract going into spasm making it more difficult for the blood to go to the lungs. The blood from the right ventricle then goes through the VSD to the aorta, which results in hypercyanosis. As the child cries, instead of returning to a normal colour when the crying stops the child remains very blue, becomes drowsy and unresponsive.

The occurrence of hypercyanotic spells require prompt referral and assessment and this is an indication for surgical intervention. An older child going through such a spell may find relief by squatting which is believed to increase the systemic vascular resistance, thereby reducing the intracardiac right to left shunting. This is now less commonly seen as the majority of children with Tetralogy of Fallot are operated in the first year of life.

• Thrill left upper sternal border
• Parasternal heave
• Quiet or absent pulmonary heart sound (P2)
• Systolic murmur left upper sternal border present from birth

Cases

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This is a two-month-old boy with a cleft lip and palette and Tetralogy of Fallot. He had a pulmonary valvotomy at the age of two days. The cardiac findings of note are his cyanosis, his single second heart sound as he does not have a pulmonary component to his second heart sound and the loud ejection systolic murmur as the blood crosses the narrowed right ventricular outflow tract.

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This is a five-week-old baby with Tetralogy of Fallot and pulmonary atresia. He has had a right-sided Blalock-Taussig shunt through a right thoracotomy and now has a continuous shunt murmur.