Echocardiographic automatic boundary detection(ABD) is a new on-line technique which automatically outlines the left atrial endocardial border and instantly calculates the left atrial area and volume from two dimensional echocardiographic images. To determine if left atrial volume can be derived using the ABD method, 70 patients with various etiology of heart disease(mean age 51) underwent complete echocardiographic examination with both the ABD method and conventional two-dimensional echocardiographic measurement.

End-systolic left atrial volume was obtained on-line from the apical four chamber view using ABD(ABD LAVOL). Left atrial length was also measured from an apical view. Left atrial volume was calculated using ellipsoid model(2D LAVOL) and method of disc(MANUAL LAVOL) by two-dimensional echocardiography.

The end-systolic left atrial volume by ellipsoid model, method of disc and ABD were 87±31ml, 57±25 and 60±28ml, respectively. I.inear regression analysis revealed that the ABD LAVOL is closely correlated with 2D LAVOL and MANUAL LAVOL(ABD LAVOL vs 2D LAVOL, SEE=22ml, r=0.65, p<0.001; ABD LAVOL vs MANUAL LAVOL, SEE=6ml, r=0.97, p<0.001).

ABD echocar-diography is a new on-line technique which may be used to accurately calculate left atrial volume in patients with various heart diseases.