Left atrial appendage

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Left atrial appendage
Heart seen from above. (Left auricula labeled at bottom left.)
Section of the heart showing the ventricular septum. (Left auricula labeled at upper right.)
Latin auricula sinistra
Gray's p.533

The left atrial appendage (LAA)[1] (also known as the left auricular appendix,[2] auricula[2] or left auricle[3]) is a muscular pouch connected to the left atrium of the heart.

It has a distinct embryologic origin.[4]


Although the LAA is sometimes called the left auricle,[5] in older texts the term "left auricle" was often used differently to describe the structure now known as the left atrium.


The LAA is a small pouch located high in the left atrium; it is within the pericardium and has a wall adjacent to the left ventricle. It appears to "function as a decompression chamber during left ventricular systole and during other periods when left atrial pressure is high".[6]

Clinical significance[edit]

In patients with atrial fibrillation, mitral valve disease, and other conditions, blood clots have a tendency to form in the LAA.[6] Blood clots caused by atrial fibrillation stem from the LAA in more than 90% of cases.[7] They may dislodge (forming emboli), which may lead to ischemic damage to the brain, kidneys, or other organs supplied by the systemic circulation.[8] Left atrial appendage occlusion is an experimental treatment to prevent stroke in atrial fibrillation.[9]

It can serve as an approach for mitral valve surgery.[10]


Functions as a reservoir for the left atrium.[citation needed]


The left atrial appendage can be seen on a standard posteroanterior x-ray, where the lower level of the left hilum becomes concave.[11]

Additional images[edit]


  1. ^ Akdeniz B, Badak O, Bariş N, et al. (March 2006). "Left atrial appendage-flow velocity predicts cardioversion success in atrial fibrillation" (– Scholar search). Tohoku J. Exp. Med. 208 (3): 243–50. doi:10.1620/tjem.208.243. PMID 16498232. [dead link]
  2. ^ a b "Gray's Anatomy". Retrieved 2008-12-14. 
  3. ^ Netter, Frank H. (1989). "Section III: Thorax". Atlas of Human Anatomy (2nd ed.). East Hanover, NJ: Novartis. ISBN 978-0-914168-81-2. 
  4. ^ Donal E, Yamada H, Leclercq C, Herpin D (September 2005). "The left atrial appendage, a small, blind-ended structure: a review of its echocardiographic evaluation and its clinical role". Chest 128 (3): 1853–62. doi:10.1378/chest.128.3.1853. PMID 16162795. 
  5. ^ Drake, Richard et al. (2010). Gray's Anatomy for Students. Churchill Livingstone. ISBN 978-0-443-06952-9. 
  6. ^ a b Al-Saady NM et al (1999) Left atrial appendage: structure, function, and role in thromboembolism: Review Heart 82:547-554
  7. ^ Blackshear JL, Odell JA (February 1996). "Appendage obliteration to reduce stroke in cardiac surgical patients with atrial fibrillation". Ann. Thorac. Surg. 61 (2): 755–9. doi:10.1016/0003-4975(95)00887-X. PMID 8572814. 
  8. ^ Parekh A, Jaladi R, Sharma S, Van Decker WA, Ezekowitz MD (September 2006). "Images in cardiovascular medicine. The case of a disappearing left atrial appendage thrombus: direct visualization of left atrial thrombus migration, captured by echocardiography, in a patient with atrial fibrillation, resulting in a stroke". Circulation 114 (13): e513–4. doi:10.1161/CIRCULATIONAHA.106.617886. PMID 17000914. 
  9. ^ Stöllberger C, Schneider B, Finsterer J (December 2003). "Elimination of the left atrial appendage to prevent stroke or embolism? Anatomic, physiologic, and pathophysiologic considerations". Chest 124 (6): 2356–62. doi:10.1378/chest.124.6.2356. PMID 14665520. 
  10. ^ Guhathakurta S, Kurian VM, Manmohan, Cherian KM (2004). "Mitral valve reoperation through the left atrial appendage in a patient with mesocardia". Tex Heart Inst J 31 (3): 316–8. PMC 521780. PMID 15562857. 
  11. ^ Corne et al. (2002). Chest X-Ray Made Easy. Churchill Livingstone. ISBN 0-443-07008-3. 

This article incorporates text from a public domain edition of Gray's Anatomy.