What is the best approach for the assessment of left atrial size? Comparison of various unidimensional and two-dimensional parameters with three-dimensional echocardiographically determined left atrial volume.

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.