Presentation
Easy fatigability with episodes of cyanosis since birth.
Patient Data
Pulmonary vascularity is increased. There is cardiomegaly with prominence of the right ventricle. The main pulmonary artery is dilated. The upper mediastinal shadow is widened with convex left border resulting in a snowman appearance.
Annotated image showing the snowman sign.
Author: Vincent Tatco
License: CC-NC-BY-SA
The right atrium and right ventricle are dilated. There is an atrial septal defect resulting in a right-to-left shunt. Instead of draining into the left atrium, all pulmonary veins drain into the systemic venous circulation through a vertical vein.
Case Discussion
Total anomalous pulmonary venous return (TAPVR) is an anomaly wherein all pulmonary veins drain into the systemic veins or into the right atrium. In order for the patient to survive, an interatrial communication (right-to-left shunt), either an atrial septal defect (ASD) or patent foramen ovale (PFO), is necessary. The current case represents type I (supracardiac), the most common of the four, and accounts for 55% of TAPVR cases. The common pulmonary venous sinus drains into the right superior vena cava (SVC) through the left vertical vein and left brachiocephalic vein. On frontal chest radiographs, this cardiovascular anomaly resembles a snowman or figure of 8.
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