Andersons pediatric cardiology 1810

FIG 69.11 Fistulous communication between the hypoplastic left ventricular cavity and the ectatic circumflex artery in a heart obtained at transplantation from a patient with hypoplastic left heart syndrome with mitral stenosis Pulmonary Atresia With Intact Ventricular Septum The morphologic variations found in the setting of pulmonary atresia with an intact ventricular septum show how the same lesion can be found as either a functionally univentricular or a functionally biventricular entity The overall morphologic features of pulmonary atresia found with an intact ventricular septum was discussed in Chapter 43 There we stressed how mural hypertrophy was the key to phenotypic variation, although some of the patients with the worst clinical prognosis had ventricular dilation, as opposed to cavitary hypoplasia, as their major feature These patients present with “wall-to-wall” hearts and could be candidates for conversion to the Fontan circulation More frequently, it is the patients having gross mural hypertrophy who will be most likely to be put forward for treatment using the Fontan approach In these patients, with the ventricular septum being intact, the right ventricle possesses its expected inlet, apical trabecular, and outlet components.16 The mural hypertrophy, however, is sufficiently great to have squeezed out the cavities of both the apical and outlet components In consequence, the ventricular cavity is represented effectively by only the inlet, with the tricuspid valve being grossly hypoplastic in keeping with the diminished size of the ventricle (Fig 69.12) and, as in those with tricuspid atresia, necessitating a surgical strategy leading to construction of the Fontan circulation The obliteration of the subpulmonary infundibulum means that it is unusual to find evidence of any remnants of the pulmonary valvar leaflets Instead, triradiating sinuses are seen within the pulmonary root (see Fig 69.12, right) Fistulous communications between the hypoplastic right ventricular cavity and the epicardial coronary arteries are more commonly found in these patients.17 The changes induced in the coronary arteries, which become ectatic, contribute still further to the poor clinical prognosis Such hearts are functionally univentricular despite being anatomically biventricular (Fig 69.13) FIG 69.12 Functionally univentricular end of the spectrum of lesions found in the setting of pulmonary atresia with an intact ventricular septum Left, The mural hypertrophy has squeezed out the cavities of the apical trabecular and outlet ventricular components, leaving the cavity effectively represented by the hypoplastic inlet component When viewed from the aspect of the pulmonary trunk (right), there is minimal evidence of the pulmonary valvar leaflets, with the root represented by the triradiating valvar sinuses