Method for separate analysis of inflow vs. outflow regions of the right ventricle in Ebstein's anomaly
© Lee et al; licensee BioMed Central Ltd. 2009
Published: 28 January 2009
Ebstein's anomaly (EA) is caused by underdevelopment of the inlet. However the impact of EA on regional and global function in the underdeveloped inlet has been difficult to assess quantitatively.
The global RV ejection fraction (EF) was mildly depressed in EA patients (45 ± 8 vs. 55 ± 4% in normals, p < 0.001). Their RV's were severely dilated (end diastolic volume index 185 ± 78 vs. 82 ± 16 ml/m2, p < 0.001) and rounded in apical and mid RV cross sections. The tricuspid annulus was severely tilted (62 ± 26 vs. 19 ± 9° in normals, p < 0.001). The infundibulum contained approximately 1/5th of RV volume in both groups (20 ± 7 in normals vs. 21 ± 9% in EA, p = NS). In EA patients inlet EF exceeded infundibulum EF (46 ± 7 vs. 38 ± 13%, p < 0.02). However the function of both inlet and infundibulum were depressed compared to normal (p < 0.05 for both). The function of the inlet and infundibulum differed less in normals (55 ± 6 vs. 49 ± 11%, p = NS). Regional function was depressed compared to normal in all 9 inlet regions, significantly so in 4 regions. Tricuspid descent was also depressed compared to normal (13 ± 5 vs. 18 ± 3 mm, p < 0.005) but the pattern of regional function was similar to normal with the greatest contraction occurring in basal regions. The global EF correlated with wall motion in the basal regions and inlet septum (r between 0.43 and 0.58, p < 0.05) and with tricuspid annular descent (r = 0.52, p < 0.005).
Despite underdevelopment of the inlet, patients with EA have relatively preserved function in this portion of the RV. Three dimensional surface reconstruction enables separate analysis of the inlet and infundibulum portions of the RV as well as detailed assessment of regional function and shape.
This article is published under license to BioMed Central Ltd.