consist of a large left (L) to right (R) shunt, which causes
severe pulmonary (lung) vascular disease and high blood pressure
(in the lungs) with resulting reversal of the direction of shunting
(figure 23F). This shunting with increase pressure causes the
lung arteries to narrow due to thickening of their walls (especially
the middle wall, called tunica media, see figure 23F) and cause
obstruction. Initially the changes may be reversible, but ultimately
they become irreversible due to inflammation of the arteries.
Hence, much of the lung arteries are occluded, leading to increase
pulmonary blood vessel resistance. Ultimately the resistance
in the lungs may exceed the resistance in the arteries of the
rest of the body, which leads to a reversal of flow from left-to-right
to right-to-left shunt.
reversal of the shunt leads to cyanosis, as well as shortness
of breath, coughing up blood, reduced exercise tolerance, syncope
(fainting), palpitations, and atrial fibrillation (see figures
15A, B). Brain events such paradoxical embolus, thrombosis (stroke)
and hemorrhage may occur. Heart failure suggest a poor prognosis,
and sudden death is possible.
swelling (clubbing) may occur. Heart murmurs may occur .
may show RVH and atrial arrhythmias (see figures 2, 3a, 3b,
5a, 5b, 14, 15a, 15b).
shows RV pressure overload, pulmonary high blood pressure, and
the underlying heart defect. Using intravenous contrast injections
along with echocardiogram will visualize the intracardiac defect.Heart
catherterization is necessary to assess the lung hypertension
and the size of the defect.
of survival is 80% 10 years after diagnosis, 77% at 15 years,
and 42% at 25 years. Death is usually sudden, presumably due
to arrhythmias, but some die of the above mentioned complications.
transplantation with repair of the cardiac or combined heart-lung
transplantation is an option for patients with a poor prognosis
(failing to respond to medical therapy).