DDX of Characteristic Heart Shapes

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