Echocardiographic features of the morphologically right ventriculo-arterial junction

Abstract

In the normal heart, the morphologically right ventricle supports the pulmonary trunk. The key to echocardiographic evaluation of the junction between these structures is to understand not only the arrangement of the pulmonary valve, but also the complete muscular infundibulum that supports the valvar leaflets, lifting the valvar complex away from the base of the ventricular mass. As explained in the previous review,1 it is the presence of this free-standing muscular infundibular sleeve that makes it possible for the surgeon to remove the pulmonary valve for use as an allograft in the Ross procedure.2 In this review, we will address the echocardiographic features of the junction, considering primarily the situation in which the morphologically right ventricle supports the pulmonary trunk, but making comparisons with the abnormal arrangements in which either the aorta, or both arterial trunks, arise from the right ventricle. As we will see, the basic arrangement of the free-standing complete muscular infundibulum, or conus, is preserved with these abnormal arrangements, but there can be variation depending on the precise arrangement of the inner heart curvature, or ventriculo-infundibular fold, and the morphology can be further changed depending on the relationship of the arterial trunks themselves. The key to analysis, therefore, and also to accurate description, is to analyse separately the way in which the arterial trunks are joined to the ventricular mass, the relationships of the trunks one to the other, and the precise structure of the supporting right ventricular outflow tract, or outflow tracts in the setting of double outlet connection. If each of these features is then described in its own right, avoiding the temptation to make inferences regarding one feature from knowledge of another, then it is possible to avoid many of the persisting controversies relating to nomenclature.