Page 160 - Clinical Pearls in Cardiology

148 Clinical Pearls in Cardiology

to the continuous flow of blood in the same direction
during both systole and diastole. Continuous murmurs
begin in systole, peak near the second heart sound and
continue into all or part of the diastole. The common
causes of continuous murmur are the following:
• Patent ductus arteriosus: Upper left sternal border
(called as the machinery Gibson’s murmur)
• Rupture of sinus of valsalva aneurysm: Upper right
sternal border
• Arteriovenous fistula
• Venous hum: Right supraclavicular fossa of normal
healthy young adults
• Mammary souffle: Over the breasts of pregnant ladies
in the third trimester.
14. What are the components of tetralogy of Fallot?
Tetralogy of Fallot (TOF) is the most common cyanotic
congenital heart defect after infancy. TOF associated
with an ASD is, sometimes, referred to as the Pentalogy
of Fallot. TOF is characterized by the following four
essential features:
1. A large (nonrestrictive) sub-aortic ventricular septal
defect
2. An aorta that overrides the ventricular septal defect
3. Obstruction of the right ventricular outflow tract
(infundibular stenosis) which produces the loud
mid-systolic murmur at the mid to upper left sternal
border. This is the only murmur heard in a case of
TOF. The shunt remains silent. Because of the
infundibular pulmonary stenosis, S2 is usually single
(P2 is soft or absent). The combination (i.e. 1 + 3)
results in elevated right ventricular pressure and right
to left shunting of blood, producing cyanosis. Those
with minimal outflow tract obstruction will have