Abstract 15276: Echocardiographic Features Defining Right Ventricle Dominant Unbalanced Atrioventricular Septal Defect: a Multi-institutional Congenital Heart Surgeons' Society Study

Objectives: Right ventricle (RV) dominant unbalanced atrioventricular septal defect (AVSD) remains challenging with regard to definition and management. We sought to assess which echo features best characterized patients based on functional and anatomic features. Methods: From a cohort of AVSD patients at 4 CHSS institutions (2000-2006), diagnostic echos of 60 randomly selected balanced patients and all 52 RV dominant patients (based on atrioventricular valve (AVV) index) underwent detailed review. Cluster analysis of these variables was used to group patients with similar features based on the echo data. Discriminant function analysis was used to determine which variables differentiated these groups. Results: Three groups were identified from the cluster analysis. Discriminant function analysis found that the echo variables that differentiated these groups were the RV:left ventricle (LV) inflow angle (RV/LVinflow), LV width/LV length, left AVV color diameter at smallest inflow, left AVV color diameter at annulus, right AVV overriding left atrium, and LV width. Outcomes associated with the 3 groups indicated that one group (1) represented balanced patients, while two groups (2,3) with similar outcomes represented unbalanced patients (Table). The dominant differentiating variable was RV/LVinflow (partial R2=0.86) (Figure), which we defined as the angle between the base of the RV and LV free wall, using the top of the ventricular septum as apex of the angle. Conclusions: The angle of RV/LVinflow is an important defining echo measure of RV dominance in patients with right unbalanced AVSD. The utility of this measure needs to be confirmed with a prospective study. ![Graphic][1] ![Graphic][2] [1]: /embed/inline-graphic-1.gif [2]: /embed/inline-graphic-2.gif