Left atrial volume

The volume of the heart's left atrium (left atrial volume) is an important biomarker for cardiovascular physiology and clinical cardiology. It is usually calculated as left atrial volume index in terms of body surface area.

Measurement

The left atrial volume is commonly measured by echocardiography or magnetic resonance tomography. It is calculated from biplane recordings with the equation:

${\displaystyle {A}_{L}={\frac {8}{3\pi }}{\frac {A4c\cdot A2c}{L}}}$

where A4c and A2c denote LA areas in 4- and 2-chamber views respectively, and L corresponds to the shortest long-axis length measured in either views. ^[1]

Usually, the volume of the left atrium is divided by the body surface area in order to provide an extensive property, which is independent from body size. ^{[2] [3]} The resulting index is referred to as left atrial volume index (LAVI):

${\displaystyle LAVI={\frac {{A}_{L}}{BSA}}}$

Physiology

LAVI between 16 and 34 ml/m2 is regarded as normal. 2015 ASE guidelines.

Pathophysiologiy and clinical implications

Enlargement of the left atrium is a form of cardiomegaly. Moderately increased LAVI (63 to 73 mL/m²) is associated with slightly elevated mortality hazard and severely increased LAVI (>73 mL/m²) with significantly higher hazard ratio of mortality. ^[2]

LAVI predicts survival after acute myocardial infarction, ^[4] postoperative atrial fibrillation in subjects undergoing heart surgery, ^[5] atrial fibrillation and stroke ^[6] as well as hospital admission in ambulatory patients. ^[7]

References

1. Lang, Roberto M.; Bierig, Michelle; Devereux, Richard B.; Flachskampf, Frank A.; Foster, Elyse; Pellikka, Patricia A.; Picard, Michael H.; Roman, Mary J.; Seward, James; Shanewise, Jack S.; Solomon, Scott D.; Spencer, Kirk T.; St John Sutton, Martin; Stewart, William J. (December 2005). "Recommendations for Chamber Quantification: A Report from the American Society of Echocardiography's Guidelines and Standards Committee and the Chamber Quantification Writing Group, Developed in Conjunction with the European Association of Echocardiography, a Branch of the European Society of Cardiology". Journal of the American Society of Echocardiography. 18 (12): 1440–1463. doi:10.1016/j.echo.2005.10.005. PMID   16376782.
2. Khan, Mohammad A.; Yang, Eric Y.; Zhan, Yang; Judd, Robert M.; Chan, Wenyaw; Nabi, Faisal; Heitner, John F.; Kim, Raymond J.; Klem, Igor; Nagueh, Sherif F.; Shah, Dipan J. (December 2019). "Association of left atrial volume index and all-cause mortality in patients referred for routine cardiovascular magnetic resonance: a multicenter study". Journal of Cardiovascular Magnetic Resonance. 21 (1): 4. doi: 10.1186/s12968-018-0517-0 . PMC   6322235 . PMID   30612579.
3. Maheshwari, Monika; Tanwar, Cp; Kaushik, Sk (2012). "Echocardiographic assessment of left atrial volume index in elderly patients with left ventricle anterior myocardial infarction". Heart Views. 13 (3): 97–99. doi: 10.4103/1995-705X.102149 . PMC   3503362 . PMID   23181177.
4. Møller, Jacob E.; Hillis, Graham S.; Oh, Jae K.; Seward, James B.; Reeder, Guy S.; Wright, R. Scott; Park, Seung W.; Bailey, Kent R.; Pellikka, Patricia A. (6 May 2003). "Left Atrial Volume: A Powerful Predictor of Survival After Acute Myocardial Infarction". Circulation. 107 (17): 2207–2212. doi: 10.1161/01.CIR.0000066318.21784.43 . PMID   12695291.
5. Dietrich, JW; Müller, P; Schiedat, F; Schlömicher, M; Strauch, J; Chatzitomaris, A; Klein, HH; Mügge, A; Köhrle, J; Rijntjes, E; Lehmphul, I (June 2015). "Nonthyroidal Illness Syndrome in Cardiac Illness Involves Elevated Concentrations of 3,5-Diiodothyronine and Correlates with Atrial Remodeling". European Thyroid Journal. 4 (2): 129–37. doi:10.1159/000381543. PMC   4521060 . PMID   26279999.
6. Jordan, K; Yaghi, S; Poppas, A; Chang, AD; Mac Grory, B; Cutting, S; Burton, T; Jayaraman, M; Tsivgoulis, G; Sabeh, MK; Merkler, AE; Kamel, H; Elkind, MSV; Furie, K; Song, C (August 2019). "Left Atrial Volume Index Is Associated With Cardioembolic Stroke and Atrial Fibrillation Detection After Embolic Stroke of Undetermined Source". Stroke. 50 (8): 1997–2001. doi:10.1161/STROKEAHA.119.025384. PMC   6646078 . PMID   31189435.
7. Ristow, Bryan; Ali, Sadia; Whooley, Mary A.; Schiller, Nelson B. (July 2008). "Usefulness of Left Atrial Volume Index to Predict Heart Failure Hospitalization and Mortality in Ambulatory Patients With Coronary Heart Disease and Comparison to Left Ventricular Ejection Fraction (from the Heart and Soul Study)". The American Journal of Cardiology. 102 (1): 70–76. doi:10.1016/j.amjcard.2008.02.099. PMC   2789558 . PMID   18572038.