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Total Anomalous Pulmonary Venous Return (TAPVR) is a cyanotic congenital heart defect in which all four pulmonary veins fail to connect to the left atrium (LA) and instead drain into the right atrium (RA) or systemic venous circulation, resulting in complete mixing of oxygenated and deoxygenated blood.
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Survival depends on the presence of a right-to-left shunt (e.g., atrial septal defect [ASD] or patent foramen ovale [PFO]).
https://www.youtube.com/watch?v=RMIKq92dfHE
The Pulmonary Veins, which carry blood back to the heart after it has circulated through the lungs, are not connected to the left atrium. Instead they are connected to one of the veins from the main circulation so that the blood returning from the lungs drains back to the right side of the heart. The affected babies may be blue or show signs of heart failure. Most of them require surgical repair in the newborn period.
Cardiology : Total Anomalous Pulmonary Venous Drainage. Rch.org.au. Published 2025. Accessed July 11, 2025. https://www.rch.org.au/cardiology/heart_defects/Total_Anomalous_Pulmonary_Venous_Drainage/
The Pulmonary Veins, which carry blood back to the heart after it has circulated through the lungs, are not connected to the left atrium. Instead they are connected to one of the veins from the main circulation so that the blood returning from the lungs drains back to the right side of the heart. The affected babies may be blue or show signs of heart failure. Most of them require surgical repair in the newborn period.
Cardiology : Total Anomalous Pulmonary Venous Drainage. Rch.org.au. Published 2025. Accessed July 11, 2025. https://www.rch.org.au/cardiology/heart_defects/Total_Anomalous_Pulmonary_Venous_Drainage/
Anatomical classification (Craig and colleagues, 1957):
| Type | Drainage Site | Classic Radiologic Sign |
|---|---|---|
| Supracardiac (50%) | Via vertical vein → innominate vein → SVC → RA | "Snowman sign" on CXR (in unobstructed cases) |
| Cardiac (20%) | Directly into RA or coronary sinus | RA and coronary sinus enlargement |
| Infracardiac (20%) | Via descending vertical vein → portal/hepatic/IVC → RA | Often obstructed, with pulmonary edema |
| Mixed (10%) | Multiple anomalous pathways | Variable findings |
Subtypes of totally anomalous pulmonary venous connection are based on the site of drainage of the common pulmonary venous sinus (confluence).
Walsh MJ, Ungerleider RM, Aiello VD, Spicer D, Giroud JM. Anomalous Pulmonary Venous Connections and Related Anomalies. World Journal for Pediatric and Congenital Heart Surgery. 2013;4(1):30-43. doi:https://doi.org/10.1177/2150135112458439
Central image displaying the mechanisms underlying reversed differential cyanosis (RDC) in (supra)cardiac total anomalous pulmonary venous return (TAPVR) and the suggested considerations for the screening protocol to ensure prompt detection of the anomaly: PDA patent ductus arteriosus, PPHN persistent pulmonary hypertension of the newborn, Qp pulmonary flow, Qs systemic flow, SO2 oxygen saturation.
Munneke, A.G., Lumens, J. & Delhaas, T. Diagnostic value of reversed differential cyanosis in (supra)cardiac total anomalous pulmonary venous return. Pediatr Res 97, 809–817 (2025). https://doi.org/10.1038/s41390-024-03355-5