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 viscer al heterotaxy. Methods. One hundred and twelve autopsied specimens wit h isomeric atrial appendages were studied. Results. Annular hinge poin ts with a planar orientation were found in only 7 hearts. All others s howed a nonplanar and undulating arrangement, including 7 with Ebstein s's malformation. When the posterior half of the valvar attachment was taken as a reference plane, the anterior part deviated superiorly, th e distance from the plane to the anterior point being 6.7+/-4.9% of th e circumferential length of the annulus. The ratio of the antero-poste rior diameter to the width of the annulus was smaller in hearts with b iventricular connections (0.77+/-0.15) than in those with double inlet ventricle (0.89+/-0.17, P<0.001). Reflecting this, the ratio of super ior deviation of the anterior valvar annulus compared to the antero-po sterior diameter was greater in hearts with biventricular atrioventric ular connections (P = 0.016), particularly in those with isomeric righ t appendages. No significant differences were found when the data was analyzed according to variations in ventricular morphology. Conclusion s. The precise evaluation of the annular structure of a common atriove ntricular valve may well prove to be of clinical significance so as op timally to achieve valvar annuloplasty.