HYPOPLASTIC RIGHT HEART SYNDROME

Type I	Small RV due to competent tricuspid valve (more common).
Type II	Normal/large RV secondary to incompetent tricuspid valve
Right Ventricle	Small cavity in type I / Large if tricuspid incompetence
Pulmonary Artery	Atresia of the valve Hypoplastic proximal pulmonary artery + retrograde blood flow seen on color doppler.
Atrial Septum	Secundum defect is frequently associated.
Tricuspid Valve	May be regurgitation resulting in congestive cardiac failure and hydrops Small and hyperechoic in pulmonary atresia with intact ventricular septum.
Tricuspid stenosis	Turbulence and increased velocity distal to valve.
Tricuspid atresia	No flow through the valve Valve and orifice hyperechoic and thickened.
Ventricular septal defect
Moderator Band	Do not confuse a large prominent moderator band in the right ventricle that appears to result in ventricular disproportion as a hypoplastic right ventricle. Note the normal tricuspid valve and normal perfusion of the chamber on color doppler imaging.

Video clip of Hypoplastic Right Heart

HEMODYNAMICS

There is a left to right atrial shunt through the foramen ovale. There is retrograde flow through the ductus arteriosus into the pulmonary vascular bed.

PROGNOSIS

Prostoglandin infusion to keep the ductus open has improved the prognosis.