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 regur gitation through a common atrioventricular valve can compromise the cl inical 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 isom eric atrial appendages and double inlet ventricle differs from that of the valve guarding a common junction in hearts with biventricular atr ioventricular 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 conn ections, all having a common valve guarding the atrioventricular junct ions. Results: A valve with three or four leaflets was seen more frequ ently in hearts with double inlet ventricle than in those with biventr icular atrioventricular connections (p = 0.016, chi-squared test). Com plicated multiple orifices within the valvular curtain, including abno rmal accessory orifices within a leaflet, were found in seven cases wi th 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 muscl es to a rudimentary and incomplete ventricle was seen in 23% of cases. Direct attachment of tendinous cords to the ventricular septum or par ietal wall was seen 81% of hearts with double inlet. Conclusions: Thes e features of the common valve found with double inlet atrioventricula r connection seem less suited to function as the inlet valve supportin g the systemic circulation. The recognized abnormal features should be identified preoperatively so as to plan more effective valvular plast y, or alternatively to establish different surgical strategies.