Left atrial enlargement

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Left atrial enlargement (LAE) or left atrial dilation refers to enlargement of the left atrium (LA) of the heart, and is a form of cardiomegaly.

In the general population, obesity appears to be the most important risk factor for LAE.[1] Also, a study found that LAE can occur as a consequence of atrial fibrillation (AF),[2] although another study found that AF by itself does not cause LAE. The latter study also showed that the persistent type of AF was associated with LAE, but the number of years that a subject had AF was not.[3]

LAE is suggested by an electrocardiogram (ECG) that has a pronounced notch in the P wave.[4] However, if there is atrial fibrillation, a P wave would not be present.[5] In any case, LAE can be diagnosed and measured using an echocardiogram (ECHO).

Characterizing the size of the left atrium according to its volume is preferred over a single linear dimension since enlargement can be different for different directions. For example, because of the smaller distance in the thoracic cavity between the sternum and spine, compared to the other directions, there is less room for LAE along the anteroposterior axis.[6] By approximating the shape of the left atrium as an ellipsoid, its volume can be calculated from measurements of its dimensions along three perpendicular directions.[2]

Left Atrium Size[6] Women Men
normal enlarged normal enlarged
mild moderate severe mild moderate severe
Diameter  (mm) 27–38 39–42 43–46 ≥47 30–40 41–46 47–52 ≥52
Volume  (ml) 22–52 53–62 63–72 ≥73 18–58 59–68 69–78 ≥79
Volume/BSA  (ml/m²)   16–28 29–33 34–39 ≥40 16–28 29–33 34–39 ≥40
   BSA, body surface area


  1. ^ Stritzke J, Markus MRP, Duderstadt S, Lieb W, Luchner A, Döring A, Keil U, Hense H and Schunkert H (2009-11-17). "The Aging Process of the Heart: Obesity Is the Main Risk Factor for Left Atrial Enlargement During Aging: The MONICA/KORA (Monitoring of Trends and Determinations in Cardiovascular Disease/Cooperative Research in the Region of Augsburg) Study". Journal of the American College of Cardiology 54 (21): 1982–9. doi:10.1016/j.jacc.2009.07.034. PMID 19909880. Retrieved 2009-12-02. 
  2. ^ a b Sanfilippo AJ, Abascal VM, Sheehan M, Oertel LB, Harrigan P, Hughes RA and Weyman AE (1990). "Atrial enlargement as a consequence of atrial fibrillation A prospective echocardiographic study". Circulation 82 (3): 792–7. doi:10.1161/01.CIR.82.3.792. PMID 2144217. Retrieved 2009-12-02. 
  3. ^ Osranek M, Bursi F, Bailey KR, Grossardt BR, Brown RD Jr, Kopecky SL, Tsang TS and Seward JB. (Dec 2005). "Left atrial volume predicts cardiovascular events in patients originally diagnosed with lone atrial fibrillation: three-decade follow-up". European Heart Journal 26 (23): 2556–61. doi:10.1093/eurheartj/ehi483. PMID 16141257. Retrieved 2009-12-27.  See p. 2560 Left ventricular filling pressure, LAV, and AF.
  4. ^ Edhouse J, Thakur RK, Khalil JM (2002-05-25). "ABC of clinical electrocardiography. Conditions affecting the left side of the heart.". British Medical Journal 324 (7348): 1264–7. doi:10.1136/bmj.324.7348.1264. PMC 1123219. PMID 12028984. Retrieved 2010-06-18. 
  5. ^ "Atrial Fibrillation (for Professionals)". American Heart Association, Inc. 2008-12-04. Archived from the original on 2009-03-28. 
  6. ^ a b Lang, RM; Bierig M, Devereux RB, Flachskampf FA, Foster E, Pellikka PA, Picard MH, Roman MJ, Seward J, Shanewise J, Solomon S, Spencer KT, St John Sutton M, Stewart W (March 2006). "Recommendations for chamber quantification". European Journal of Echocardiography 7 (2): 79–108. doi:10.1016/j.euje.2005.12.014. PMID 16458610. Retrieved 2012-08-26.