The structure of the common atrioventricular valve in hearts having isomeric atrial appendages and double inlet ventricle.

BACKGROUND AND AIMS OF THE STUDY: It is now well recognized that regurgitation through a common atrioventricular valve can compromise the clinical course both before and after surgical interventions in patients with visceral heterotaxy. This may reflect the anatomic structure of the valve. This study aimed to determine whether the structure of the common atrioventricular valve found in the setting of hearts with isomeric atrial appendages and double inlet ventricle differs from that of the valve guarding a common junction in hearts with biventricular atrioventricular connections.

METHODS

Sixty-three autopsied hearts with double inlet ventricle and isomeric atrial appendages were studied, in addition to 79 with isomerism and biventricular atrioventricular connections, all having a common valve guarding the atrioventricular junctions.

RESULTS

A valve with three or four leaflets was seen more frequently in hearts with double inlet ventricle than in those with biventricular atrioventricular connections (p = 0.016, chi-squared test). Complicated multiple orifices within the valvular curtain, including abnormal accessory orifices within a leaflet, were found in seven cases with double inlet to a dominant morphologically left or right ventricle. The presence of four papillary muscles was the most common pattern in hearts with double inlet ventricle. Straddling of the papillary muscles to a rudimentary and incomplete ventricle was seen in 23% of cases. Direct attachment of tendinous cords to the ventricular septum or parietal wall was seen 81% of hearts with double inlet.

CONCLUSIONS

These features of the common valve found with double inlet atrioventricular connection seem less suited to function as the inlet valve supporting the systemic circulation. The recognized abnormal features should be identified preoperatively so as to plan more effective valvular plasty, or alternatively to establish different surgical strategies.