Fetal echocardiographic features of absent pulmonary valve syndrome

Absent pulmonary valve syndrome represents a rare defect, characterized by rudimental pulmonary valve leaflets. The presence of a nonfunctional valve can result in right ventricle dilation (Figure 1) and reduced ventricular compliance. There is often a ventricular septal defect with aortic override, as seen in tetralogy of Fallot (Figure 2, Video 1) while ductus arteriosus is frequently absent (Figure 3). Pulmonary valve stenosis may coexist (Figure 4). The main sonographic feature is massive dilation of pulmonary branches (Figure 5, Video 2). The prognosis is poor, and in addition to cardiac complications, most infants develop respiratory distress secondary to compression of bronchi by dilated pulmonary arteries.