Tetralogy of Fallot is a congenital heart defect with four parts: a ventricular septal defect, narrowing of the right ventricular outflow, an aorta that overrides the septum, and right ventricular hypertrophy. Blood low in oxygen shunts into the aorta, so babies are blue, and how blue depends on how tight the outflow narrowing is.
Key symptoms
- Bluish lips and skin in a newborn or infant
- Tet spells: sudden deeper cyanosis with crying or feeding, fast deep breathing and irritability
- Older children squat to relieve breathlessness
- Poor feeding and slow weight gain
What you find on exam
- Central cyanosis and low oxygen saturation
- Harsh systolic ejection murmur at the left upper sternal border that softens during a spell
- Single second heart sound
- Clubbing in older children who were not repaired
Tests
- Pulse oximetry screening in the newborn
- Echocardiogram confirms the anatomy
- Chest X-ray: boot-shaped heart with reduced lung markings
- ECG: right axis deviation and right ventricular hypertrophy
Treatment basics
- Tet spell: calm the child, knees to chest, oxygen, then morphine, IV fluids, propranolol or phenylephrine
- Prostaglandin E1 (alprostadil) to keep the ductus open in severe newborn cases
- Complete surgical repair, usually in the first year of life
- Lifelong cardiology follow-up for pulmonary regurgitation and arrhythmias
Red flags
- Spell that does not improve with knee-chest position and oxygen
- Limpness, seizure or loss of consciousness during a spell
- Oxygen saturation that keeps falling
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; NCSBN 2026 NCLEX-RN Test Plan. Written by Making Synapses. Making Synapses is not affiliated with these organizations.