Ventricular septal defect
Ventricular septal defects (VSD) represent defects in the interventricular septum that allow a haemodynamic communication between the right and left ventricles. It typically results in a left-to-right shunt.
They represent one of the most common congenital cardiac anomalies and may be associated with up to 40% of such anomalies 1. They are considered the most common congenital cardiac abnormality diagnosed in children and the second most common diagnosed in adults 9. The estimated incidence is at ~1 in 400 births 6.
Classification according to location
- membranous/perimembranous (most common: 80-90%)
A VSD can occur on its own but frequently tends to occur with other cardiovascular associations:
- cardiovascular associations
- extra-cardiac associations
The chest radiograph can be normal with a small VSD. Larger VSDs may show cardiomegaly (particularly left atrial enlargement although the right and left ventricle can also be enlarged). A large VSD may also show features of pulmonary arterial hypertension, pulmonary oedema, pleural effusion and increased pulmonary vascular markings.
Allows direct visualisation of the septal defect which can be easily seen in the four chamber view. A perimembranous VSD can be seen as a septal dropout in the area adjacent to the tricuspid septal leaflet and below the right border of the aortic annulus. Small isolated VSDs can be difficult to detect prenatally.
CTA with ECG-gating allows direct visualisation of the defect. Large VSDs may be seen on non-gated studies.
May also show added functional information (e.g. quantification/shunt severity) in addition to anatomy. Some muscular defects can give a "Swiss cheese" appearance owing to their complexity.
Treatment and prognosis
The prognosis is good for small VSDs which show a high spontaneous intrauterine or postnatal closure rate. VSDs usually do not cause any haemodynamic compromise in utero due to the right and left ventricular pressures being very similar during that period.
- Eisenmenger phenomenon with shunt reversal (i.e. left-to-right becomes right-to-left)
- cardiac failure
Congenital heart disease
There is more than one way to present the variety of congenital heart diseases. Whichever way they are categorised, it is helpful to have a working understanding of normal and fetal circulation, as well as an understanding of the segmental approach to imaging in congenital heart disease.
congenital heart disease
- normal relationship between chambers and valves
- atrioventricular valves
- outflow tract
- great vessels
- venous inflow
- anomalous valves
- abnormal relationship of chambers and valves
- atrioventricular abnormality
- great vessel connection abnormality
- conotruncal cardiac anomalies
- pentalogy of Cantrell
- Shone syndrome
- congenital heart disease - chest x-ray approach
surgical repairs (mnemonic)
- arterial switch procedure
- Blalock-Taussig shunt
- double switch procedure
- Fontan procedure
- Glenn procedure
- Mustard repair
- Norwood procedure
- Pott shunt
- pulmonary artery banding
- Rastelli procedure
- Sano shunt
- Senning repair
- total repair of tetralogy of Fallot (TOF)
- unifocalisation procedure
- Waterston shunt
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