Pulmonary atresia with intact interventricular septum

Pulmonary atresia with intact interventricular septum (PA-IVS) is a subtype of pulmonary atresia that presents as cyanotic congenital heart disease.

Pathology

PA-IVS is the combination of obstruction of the pulmonary outflow tract from pulmonary valve atresia without a ventricular septal defect. Blood returns to the left heart via a patent foramen ovale, and a patent ductus arteriosus (PDA) is required for pulmonary blood flow.

The right ventricle is variably hypoplastic, and the right atrium is typically dilated.

Associations

• tricuspid regurgitation +/- Ebstein anomaly
• aortopulmonary collaterals (rare)
• Down syndrome (rare) 

Radiographic features

Plain radiograph

The features on chest radiographs are variable depending on associated anomalies :

• cardiomegaly may be present with severe tricuspid regurgitation
• pulmonary plethora may be present with large left-to-right shunts (from PDA or aortopulmonary collaterals)

Treatment and prognosis

The prognosis depends on the degree of atresia as well as whether it is unilateral versus bilateral. Percutaneous interventional perforation is an effective first-stage procedure.