Objective: To clarify the precise anatomic arrangement of the annular attachment of a common atrioventricular valve in the setting of visceral heterotaxy.
Methods: One hundred and twelve autopsied specimens with isomeric atrial appendages were studied.
Results: Annular hinge points with a planar orientation were found in only 7 hearts. All others showed a nonplanar and undulating arrangement, including 7 with Ebsteins's malformation. When the posterior half of the valvar attachment was taken as a reference plane, the anterior part deviated superiorly, the distance from the plane to the anterior point being 6.7 +/- 4.9% of the circumferential length of the annulus. The ratio of the antero-posterior diameter to the width of the annulus was smaller in hearts with biventricular connections (0.77 +/- 0.15) than in those with double inlet ventricle (0.89 +/- 0.17, P < 0.001). Reflecting this, the ratio of superior deviation of the anterior valvar annulus compared to the antero-posterior diameter was greater in hearts with biventricular atrioventricular connections (P = 0.016), particularly in those with isomeric right appendages. No significant differences were found when the data was analyzed according to variations in ventricular morphology.
Conclusions: The precise evaluation of the annular structure of a common atrioventricular valve may well prove to be of clinical significance so as optimally to achieve valvar annuloplasty.