Page 158 - Clinical Pearls in Cardiology

146 Clinical Pearls in Cardiology

9. What is the difference between a restrictive and a
nonrestrictive VSD?
The terms restrictive and nonrestrictive are used for
the hemodynamical classification of ventricular septal
defects. VSDs are classified as nonrestrictive when there
is no significant pressure gradient between the two
ventricles. When there is a large pressure gradient between
the two ventricles (i.e. pressure gradient more than
64 mm Hg), then the VSD is said to be restrictive. Because
of the large pressure gradient, restrictive VSDs produce
loud and long murmurs. Shunt murmur may even be
absent in a nonrestrictive VSD with very low pressure
gradient.
10. What do you know about the natural history of atrial
septal defect?
Majority of patients with the most common ostium
secundum type of ASD (i.e. central defect located in the
region of fossa ovalis) remain asymptomatic throughout
their early adulthood. They may present in middle age
with insidious onset of fatigue and breathlessness.
Symptoms of heart failure are usually progressive and
worsened with the development of atrial arrhythmias.
Patients with ostium primum ASD (i.e. atrioventricular
type of defect located in the lower part of the atrial
septum) tend to present earlier with more severe
symptoms.
On clinical examination, the classic sign of ASD
is the wide and fixed splitting of the second heart
sound, together with a systolic ejection murmur in
the pulmonary area and a mid-diastolic rumble in the
lower right sternal border, due to the increased blood