It
is characterized by a large ventricular septal deftect (VSD),
an aorta that overrides the left and right ventricles, obstruction
of the right ventricular (RV) outflow tract, and RV hypertrophy
(increased wall thickness).
As obstruction in RV outflow tract increases, more blood is
shunted through the VSD to the left side of the heart to cause
more cyanosis (see fig 23C).
Increases
in resistance to flow in the general arteries of the body causes
less shunting, and decreases cause more shunting to the left.
Symptoms
in adults include shortness of breath and limited exercise tolerance.
Complications include brain abscesses, strokes and heart infections.
Such patients may have enlargement of the distal ends of their
fingers called clubbing.
Most patients without surgical correction die in childhood.
Echocardiography
can establish the diagnosis. Color Doppler can visualize the
VSD.
Heat catherterization can confirm the diagnosis.
Surgical
repair is recommended to relieve symptoms and to improve survival.
Complete surgical correction (closure of the VSD and relief
of RV outflow obstruction is performed currently when patients
are very young.
Patients are at risk for heart infections and should thus receive
prevention with antibiotics before dental or elective surgical
procedures.
Even
with repair these patients have a poorer survival rate (apparently
due to cardiac causes such as arrhythmias).