Left atrial appendage

The left atrial appendage (LAA) is a pouch-like projection from the main body of the left atrium lies in the atrioventricular sulcus in close proximity to the left circumflex artery, the left phrenic nerve, and the left pulmonary veins.

Morphological types

Four main morphological types have been described:

  • chicken wing: 48%
  • cactus: 30%
  • windsock: 19%
  • cauliflower: 3%.

It is derived from the left wall of the primary atrium, which forms during the fourth week of embryonic development. It has developmental, ultrastructural, and physiological characteristics distinct from the left atrium proper.

It can be the source of more than 90% of cardiac-based emboli.

Some authors report that the presence trabeculations and a smaller left atrial appendage orifice diameter may be associated with greater stroke prevalence in atrial fibrillation. i.e. the risk is lowest with chicken wing, with other types carrying higher risk cactus (x 4.08), windsock (x 4.5), and cauliflower (x 8).

Thoracic anatomy
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Article information

rID: 48183
System: Cardiac
Section: Anatomy
Tag: cases
Synonyms or Alternate Spellings:
  • Left atrial appendage (LAA)

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Cases and figures

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    Case 1: elongated left atrial appendage
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