Differential diagnosis for a small cardiothoracic ratio

A small cardiothoracic ratio (CTR) is defined as <42%/0.42 when assessed on a PA chest radiograph, and is often called small heart syndrome. A pathologically-small heart is also known as microcardia.
It can be due to/associated with a number of entities:

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Article information

rID: 9884
System: Chest, Cardiac
Section: Gamuts
Synonyms or Alternate Spellings:
  • Small heart syndrome
  • Small cardiac silhouette
  • Reduced cardiothoracic ratio (CTR)
  • Low cardiothoracic ratio (CTR)
  • Decreased cardiothoracic ratio (CTR)
  • Small heart
  • Small CTR
  • Differential diagnosis for a small heart size
  • Small cardiothoracic ratio (CTR)
  • Microcardia

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