Introduction
Congenital heart defects (CHD) are the commonest birth defects: about 8 in 1000 live births. Most are multifactorial, but some come with syndromes or maternal factors. Many are now found on antenatal scans or by newborn pulse oximetry, and most can be repaired.
The main defects
Acyanotic, left-to-right shunts (more blood to the lungs)
Acyanotic, obstructive
Cyanotic (right-to-left or mixing)
Eisenmenger syndrome: a long-standing large left-to-right shunt damages the pulmonary vessels until pressure reverses the shunt, causing cyanosis. It is now rare because defects are closed early.
Finding heart disease in newborns
- Pulse oximetry screening after 24 hours: pass if SpO₂ ≥ 95% in the right hand or a foot and the difference is ≤ 3%.
- Always feel the femoral pulses.
- Hyperoxia test: in 100% oxygen, arterial PaO₂ stays low (under about 150 mmHg) in cyanotic heart disease but rises in lung disease.
Innocent murmurs
Heard in up to half of children, louder with fever. Features: systolic (except the venous hum), soft, short, at the left sternal edge, changing with posture, normal heart sounds, no symptoms, normal pulses. Examples: Still's murmur (vibratory), pulmonary flow murmur, venous hum (continuous, disappears lying down). Refer if diastolic, loud (with thrill), with symptoms or in a newborn.