Single-plane and biplane 2D algorithms and non-atrial specific 3D echo softwares underestimate left atrial volumes in comparison with specific 3D echo software tailored for left atrium

Background: Left atrial (LA) volumes are well-known predictors of cardiovascular outcome in a variety of heart diseases. However, LA is a 3D asymmetric structure and its volume calculations using 2D echo methods may be hampered by geometrical assumptions about its shape, acquisition of foreshortened or off-axis LA views. To partially overcome these limitations 3D echo has been used, but no 3D software specifically tailored for the LA quantitation has been available until recently. We sought to assess the influence of the echo technique and the algorithm used on LA volume measurement. Methods and results: 58 healthy volunteers aged 18 to 65 (38+12 years, 31 women) with good acoustic window, underwent acquisition of 2D apical 4- and 2-chamber views for the assessment of the LA and a 3D full-volume data set from apical approach (31+6 vps) for LA quantitation. LA volumes were calculated on 2D images using both single- and bi-plane disc summation algorithms. 3D LA data sets were quantitated using a software developed for the left ventricle (4D AutoLVQ, GE Healthcare, Horten N) and adapted to LA volume measurements, as well as with a novel semi-automatic software tailored for LA quantitation developed by TomTec (Unterschleissheim,Germany). Comparison of LA maximal and minimal volumes obtained using the 4 algorithms are summarized in the Table. Conclusions: In comparison to LA volumes obtained using a 3D software dedicated for LA analysis, both 2D algorithms and the non-atrial specific 3D software underestimate significantly LA volumes. Whether the implementation of atrial-specific 3D softwares could improve the prognostic stratification of patients with LA enlargement in various conditions remains to be verified.