Ventricular septal defect. A review of current thoughts.

Ventricular septal defect, alone or in combination with other cardiac malformations, is the commonest form of congenital heart disease in man. Morphogenically, the ventricular septum is composed of three parts: (a) the conal septum, (b) the septum of the endocardial cushions, and (c) the muscular septum proper. Consequently, most cono-truncal abnormalities (transposition of the great arteries, tetralogy of Fallot, common truncus arteriosus) include a defect of the ventricular septum and, similarly, most endocardial cushion defects (and all complete AV canals) have a ventricular compo- nent. Isolated ventricular septal defects may occur in any of the three parts. The majority of the complex intracardiac malformations are associated with a ventricular septal defect.