total anomalous pulmonary venous return
Summary
Total anomalous pulmonary venous return (TAPVR) is a rare congenital heart defect where all pulmonary veins drain into the right atrium or systemic venous circulation instead of the left atrium. An atrial septal defect (ASD) must be present for survival, allowing mixing of oxygenated and deoxygenated blood. This results in cyanosis and congestive heart failure in infancy.
Detail
TAPVR occurs when all four pulmonary veins fail to connect normally to the left atrium during embryonic development. Instead, they drain into systemic venous structures such as the superior vena cava, coronary sinus, right atrium directly, or portal venous system. This creates a situation where oxygenated blood from the lungs returns to the right side of the heart rather than the left atrium. For survival, an atrial septal defect must be present to allow some oxygenated blood to reach the left atrium and systemic circulation. The condition is classified into four types based on drainage location: supracardiac (45% - drains to SVC), cardiac (25% - drains to coronary sinus or right atrium), infracardiac (25% - drains below diaphragm), and mixed (5%). Infracardiac type often presents with obstruction and severe symptoms early. Clinical presentation includes cyanosis, tachypnea, poor feeding, and congestive heart failure. Chest X-ray may show the characteristic 'snowman' or 'figure-of-8' appearance in supracardiac type. Surgical repair involves redirecting pulmonary venous drainage to the left atrium and is typically performed in infancy.
Sources
- Robbins and Cotran Pathologic Basis of Disease
- Nelson Textbook of Pediatrics
- Moss and Adams' Heart Disease in Infants, Children, and Adolescents
- First Aid for the USMLE Step 1
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