Approach to the DDX of characteristic heart shapes:
- Egg on a string – transposition of the great arteries – heart appears egg shaped due to abnormal convexity of right atrial border+left atrial enlargement while superior mediastinum appears narrow due to stress-induced thymic atrophy+hyperinflated lung
- Snowman – total anomalous pulmonary venous return supracardiac – upper half is dilated superior vena cava on right + left vertical vein on left, lower half is enlarged right atrium
- Scimitar – partial anomalous pulmonary venous return – right pulmonary vein drains below diaphragm into inferior vena cava / hepatic veins
- Boot – tetralogy of Fallot – upward pointing cardiac apex due to right ventricular hypertrophy
- Gooseneck – AV canal – elongation of the left ventricular outflow tract on angiogram
- Box-shaped – Ebstein’s anomaly – atrialization of right ventricle due to displaced tricuspid valve
- Water bottle – pericardial effusion – large amount of fluid in pericardial space
- Figure 3 – coarctation of the aorta – prestenotic dilation ascending aorta / coarctation / post-stenotic dilation descenging aorta
