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Congenital Heart Disease 145

perimembranous subaortic VSDs may be associated
with aortic regurgitation. Patients with VSD and aortic
regurgitation most commonly present with a new
diastolic murmur of aortic regurgitation, syncope
secondary to right ventricular outflow tract obstruction
caused by the prolapsing coronary cusp, or heart failure
due to progressive left ventricular volume overload.
Patients who have small VSDs and patients whose VSDs
are associated with aortic regurgitation are at high-risk
for endocarditis because of the highly turbulent jet.
8. What is the peculiarity of the murmur of ventricular
septal defects located in the muscular part of the
interventricular septum?
Most VSDs are located in the membranous part of the
interventricular septum and they cause the classical
holosystolic murmur. Defects located in the muscular
part of the interventricular septum are often multiple
(swiss-cheese septum). They cause an early systolic
decrescendo murmur. This is because the contraction of
the muscular septum towards the end of systole leads to
the closure of septal defect. This abolishes the later part
of the murmur, making it early systolic in timing (Fig. 3).

Fig. 3: Murmur in ventricular septal defect