The reasons for the worse prognosis of these patients compared
with patients with Eisenmenger Syndrome are unclear and
include the lack of a possible pulmonary-to-systemic shunt in the
case of elevation of PVR or impaired adaptation of the right ventricle
to an increasing after-load when this starts after the first
months/years of life. This last hypothesis may be confirmed by a
higher value of right atrial pressure (pre-load) despite lower PVR
(after-load) in patients with corrected defects compared with
the Eisenmenger Syndrome patients of our study (Table 2).