Clinical and morphologic features of perimembranous ventricular septal defect with overriding of the aorta - The so-called Eisenmenger ventricular septal defect. A study making comparisons with tetralogy of Fallot and perimembranous ventricular defect without aortic overriding

The aim of our study was to elucidate the clinical and morphologic features of those perimembranous ventricular septal defects which extend between the ventricular outlets, particularly when found in association with anterior deviation of the muscular outlet septum and overriding of the aorta -the so called Eisenmenger ventricular septal defect. From 1990 through 1998, we have undertaken surgical correction in 203 patients with perimembranous ventricular septal defect. Of these, 15 patients had the Eisenmenger ventricular septal defect. We conducted retrospective analyses of the clinical records, catheterization data, and angiocardiographic and echocardiographic finding of these patients. Comparative studies were then made with the patients having tetralogy of Fallot, and those with simple perimembranous ventricular septal defects without overriding of the aorta. In the patients with the Eisenmenger ventricular septal defect, the extent of anterior deviation of the outlet septum was comparable with that seen in tetralogy of Fallot, but there was less rightward displacement of the aortic valvar orifice. In contrast to earlier investigators, however, we found evidence of progressive narrowing of the subpulmonary infundibulum in those with the Eisenmenger defect. These morphological features were reflected in the clinical features, since all patients showed evidence of increased pulmonary flow and congestive heart failure in early infancy, but with two-thirds of them subsequently developing right-to-left shunting. We conclude, therefore, that the Eisenmenger ventricular septal defect is a discrete cardiac abnormality in which the morphologic substrate of anterior deviation of the outlet septum gives rise to a potential for progressive narrowing of the subpulmonary infundibulum. Surgical management, therefore, needs to take account of such narrowing as an additional cardinal morphologic feature.