Hypoplastic right heart syndrome (HRHS)

Hypoplastic right heart syndrome is a congenital cardiac anomaly. It is characterized by an underdeveloped right side of the heart, including the right ventricle, tricuspid valve, pulmonary valve, and pulmonary arteries.

Epidemiology

It may be present in around 1.1% of stillbirths and is rarer than the hypoplastic left heart syndrome.

Clinical presentation

Neonates are cyanotic at birth.

Pathology

It is caused by decreased blood flow in and out of the right ventricle during development. The most common right-sided defect to cause this syndrome is pulmonary atresia with an intact ventricular septum. Coronary arterial supply may be also abnormal.

Radiographic features

Fetal echocardiography

Prenatal ultrasound may show a small right ventricle with hypertrophy and a small or absent pulmonary artery, with decreased or absent flow through the tricuspid valve and pulmonary valve.