The infundibular interrelationships and the ventriculoarterial connection in double outlet right ventricle. Clinical and surgical implications.

Fifty specimens of double outlet right ventricle were studied. The insertion of the outlet (infundibular) septum determines two types of infundibular interrelationships. In the first type, with anterior and posterior infundibulums, the outlet septum is inserted to the anterior limb of the septomarginal trabeculation; the posterior infundibulum is related with the atrioventricular orifices and the interventricular septum forms exclusively one of the walls of the posterior infundibulum. Therefore, the artery connected with the posterior infundibulum may be related with a subarterial ventricular septal defect. Of our material, 35 cases (70% of 50) had anterior and posterior infundibulums and, in 32, the aorta was connected with the posterior infundibulum (91.4% of 35). The ventricular septal defect was subaortic in 26 cases (81.2% of 32). In the second type, with side-by-side infundibulums, the outlet septum is inserted in to the ventriculo-infundibular fold in the proximity of the posterior limb of the septomarginal trabeculation. Both infundibulums are related with the atrioventricular orifices and the interventricular septum forms exclusively one of the walls of the medial infundibulum. Therefore, the artery connected with the medial infundibulum has the possibility of being related with a subarterial ventricular septal defect. Of our material, 13 cases (26% of 50) had side-by-side infundibulums. In all of these (100% of 13), the pulmonary trunk was connected with the medial infundibulum and the ventricular septal defect was subpulmonary in 12 cases (92.3% of 13). There were two cases (4% of 50) with a doubly committed ventricular septal defect. The insertion of the outlet septum permits one to determine the infundibular interrelationships, information which cannot be attained by taking into account the relationship of the great arteries with each other. Once the infundibular interrelationship is established, one must determine if the aorta is connected with the posterior or with the medial infundibulum, since, depending on the anatomical constitution of these infundibulums, there is the possibility of a ventricular septal defect being related with this artery. This information is indispensable before attempting the surgical correction of the double outlet right ventricle and it may be obtained by echocardiography or by angiocardiography.