The differentiation of pulmonic stenosis, ventricular septal defect with normal aortic root from tetralogy of Fallot

A physiologic and clinical approach has been employed to distinguish two groups of patients who were anatomically similar: one group had pulmonic stenosis, ventricular septal defect with overriding aorta (tetralogy of Fallot); and the second group had pulmonic stenosis, ventricular septal defect with normal aortic root. The former group has a single developmental defect associated with incomplete transposition of the aorta and persistence of a right ventricular aortic flow; therefore, this entity should be considered within the spectrum of the transpositions. The second group, whether in utero development of pulmonic stenosis with interventricular septal defect or postnatal hypertrophy of the right ventricular outflow tract with interventricular septal defect, has evidence of a hyperdynamic left ventricle. It is the physiologic role of the left ventricle that separates these patients into two distinct groups.