Page 156 - Clinical Pearls in Cardiology

144 Clinical Pearls in Cardiology

As the septum primum reaches the endocardial
cushions and closes the foramen primum, a second
opening called the foramen secundum appears in the
septum primum. This is to permit flow of blood from
the developing right atrium to the developing left side
of the heart. As foramen secundum enlarges, a second
septum called the septum secundum forms to the
right of septum primum. Septum secundum forms an
incomplete partition that leaves an opening, the foramen
ovale. Normally the foramen ovale closes in the first
three months following birth due to the fusion of septum
primum and septum secundum. This fusion leaves a
remnant of the foramen ovale known as the fossa ovalis.
7. What do you know about the natural history of
ventricular septal defect?
Small VSDs are usually asymptomatic and compatible
with a normal life (about 40% close spontaneously in early
childhood). The phrase “maladie de Roger” is used to
refer to a small asymptomatic ventricular septal defect.
Large VSDs cause cardiac failure in the 2nd or 3rd month
after birth. If a large shunt does not produce symptoms
during infancy, then there is little disturbance until late
adolescence or early adult life, when the patient may
develop pulmonary artery hypertension due to increased
pulmonary blood flow resulting from the left-to-right
shunt. This leads to breathlessness, fatigue and cyanosis.
Eventually severe heart failure develops.
On clinical examination, the classic sign is a loud
holosystolic murmur (sometimes with a systolic thrill)
in the mid to lower left sternal border. In addition, there
may be a mid-diastolic flow murmur in the mitral area.
Later on, as pulmonary vascular resistance increases,
this holosystolic murmur shortens in duration. Large