Morphology of the atrioventricular valve in patients with right atrial isomerism.

Abstract

We read with interest the paper of Kawahira et al. [ 4] on morphologic analysis of common atrioventricular valves in patients with right atrial isomerism. We completely agree with the authors about the peculiar morphologic features of the atrioventricular valve in these patients, as we [3] and Uemura et al. [5] already described. In fact, observing our 33 specimens with asplenia syndrome, we reported some anatomic peculiarities including: (1) high prevalence of ventricular inversions (39% ), (2) high prevalence of right ventricular dominance (82%), and (3) a reduced number of AV valve leaflets and papillary muscles. Uemura et al. [5] noted in their 35 hearts with isomeric right appendages that the diameter and length of the papillary muscles were significantly smaller, as were the distances between the papillary muscles and the cir­ cumference of the mural leaflet. These observations and the findings described by Kawahira et al. [ 4] suggest that the peculiar morphologic characteristics of the A V valve may be the cause of the frequent valvar regurgitation in these patients. The knowledge of this characteristic anatomic substrate may be useful for correct surgical treatment in patients with AVSD and AS. Probably these peculiar and repetitive anatomic fea­ tures are related to the specific genetic background of patients with asplenia/right isomerism [1-2].