Classic patterns of CHD seen on X rays
- • Transposition of the great vessels : “egg on a string” sign due to narrowing of the superior mediastinum (creating the “string”) related to stress-related thymic atrophy, lung hyperinflation, and abnormal relationship of the great vessels, along with abnormal convexity of the right atrial contour and left atrial enlargement (creating the “egg” on its side). This condition is due to ventriculoarterial discordance, where the aorta arises from the right ventricle and the pulmonary artery arises from the left ventricle.
- • Tetralogy of Fallot : “boot-shaped heart” due to uplifting of the cardiac apex caused by right ventricular hypertrophy and a convex margin where the shadow of the main pulmonary artery should be. Associated decreased pulmonary vascularity is also typically seen. This condition is the most common cyanotic CHD of childhood and has four characteristic features: right ventricular outflow tract obstruction, an overriding aorta, a VSD, and right ventricular hypertrophy.
- • Ebstein anomaly : “box-shaped heart” due to marked cardiac, in particular right atrial, enlargement and abnormal left cardiac contour related to displacement of the right ventricular outflow tract. This condition is due to atrialization of a portion of the right ventricle caused by an abnormal tricuspid valve.
- • TAPVR (type 1) : “snowman” sign (or “figure of 8” sign) where a dilated vertical pulmonary vein on the left, innominate vein on the top, and superior vena cava form the “head” of the snowman, and an enlarged heart, including an enlarged right atrium, form the “body” of the snowman.
- • Partial anomalous pulmonary venous return (PAPVR) (venolobar type) : “scimitar” sign as described below.