Total anomalous pulmonary venous return (TAPVR)

Total anomalous pulmonary venous return (TAPVR) is a congenital cyanotic condition resulting from failure of connection between the pulmonary veins and the left atrium.

Instead, the pulmonary veins drain to systemic veins or directly to the right atrium.

Therefore, an interatrial shunt such as an atrial septal defect (ASD) or patent foramen ovale (PFO) is required for survival.

TAPVR accounts for 1–2% of cardiac malformations and can occur with other cardiac abnormalities and heterotaxy syndrome, especially asplenia.

TAPVR usually presents in the first 2 weeks of life.
The presence of pulmonary venous obstruction determines the
severity and clinical features.

TAPVR with supracardiac (type I) or cardiac (type II) pulmonary venous drainage without pulmonary venous obstruction presents with pulmonary overcirculation and pulmonary hypertension from
left-to-right shunting.

Patients may have dyspnea, poor feeding, poor growth, or mild cyanosis.

In contrast, TAPVR with pulmonary venous obstruction, most commonly infracardiac (type III), has pulmonary venous hypertension and inadequate pulmonary blood flow.

Patients present with cyanosis, respiratory distress, and poor growth.

Chest radiograph
– Type 1 : Classic “snowman” appearance in older children
The snowman pattern is less specific in infancy because of prominence of the thymus
– Type 2 : indistinguishable from ASD on plain film, with cardiomegaly and shunt vascularity
– Type 3 : Small heart and pulmonary edema
– Mixed type : variable appearance