Left atrial appendage

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Left atrial appendage
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Heart seen from above. (Left auricula labeled at bottom left.)
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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]

Terminology[edit]

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.

Function[edit]

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]

Function[edit]

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

Radiology[edit]

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]

References[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.