Background: Coexistence of abnormalities in both atrioventricular and ventriculoarterial junctions occasionally represents a formidable challenge to the surgeon. Association of atrioventricular septal defect (AVSD) with common arterial trunk is such an example. To date, only two reports have described successful operative outcome. This paucity of success might reflect the anatomical complexity that could prevent favourable result.

Methods: We reviewed 6 specimens with AVSD and common arterial trunk, focusing on how to establish a non-obstructed connection between the left ventricle (LV) and the truncal valve.

Results: In all cases, the common trunk arose exclusively from the right ventricle (RV), and the only exit from the LV was the ventricular component of AVSD (Fig). In particular, preferential route was limited to a space below the superior bridging leaflet (SBL) that did not have any tendinous cords inserting onto the ventricular crest in contrast to the inferior bridging leaflets (IBL) that were always tethered to the crest with many short cords. Accordingly, the size of potential LV outflow depended on the shape of the antero-superior margin of the ventricular crest below the SBL. The potential outflow was narrower than the truncal valvar area in all hearts but one having extensive antero-superior excavation of the ventricular crest, suggesting the necessity of septal enlargement had anatomical repair been attempted during life.

Conclusions: Owing to the unique ventriculoarterial connection, the surgeon, considering anatomical repair, needs to pay attention to the antero-superior margin of the ventricular scoop, which determines the adequacy of LV outflow size.