Background: Left atrial (LA) size has prognostic importance in a variety of cardiac conditions. Diameters, area, or volume derived from 2-dimensional (2D) echocardiography (2DE) are commonly used to measure LA size, but involve numerous assumptions. This study examined the accuracy of these 2DE parameters compared to 3-dimensional echocardiographic LA volume (3DV).
Methods: LA diameters, area, and volume measured from 2DE were correlated with 3DV in 118 patients with dilated cardiomyopathy, hypertrophic cardiomyopathy, or without structural heart disease.
Results: Diameter (anterior-posterior, superior-inferior, and medial-lateral) and 2DE area measurements had statistically significant, but modest, correlations with 3DV, and exhibited a large degree of scatter in comparison with 3DV. The 2DE-derived volume had an excellent correlation with 3DV, but consistently underestimated LA volume.
Conclusion: The 2DE LA volume correlates better than other parameters with 3DV, but often results in underestimation. Thus, caution should be exercised when using unidimensional and 2D measurements of LA size.