The nature of the annular attachment of a common atrioventricular valve in hearts with isomeric atrial appendages

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.