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.
Clinical presentation varies depending on the size and resultant severity of the VSD 10. Small lesions with minimal shunting may be asymptomatic, however may have a loud harsh pansystolic murmur heard on praecordial ausculation over the left sternal border 10. Larger lesions, in comparison, may cause signs of heart failure such as exertional dyspnoea, raised jugular venous pressure, hepatomegaly, peripheral oedema, or failure to thrive in paediatric patients, but may have a very soft murmur 10.
In addition to a pansystolic murmur, there may also be a mid/end diastolic murmur mimicking mitral stenosis as well as an ejection systolic murmur mimicking aortic stenosis, each due to increased pulmonary circulation compared to systemic circulation resulting in more total blood passing through the left atrium and ventricle 10. Cyanosis is generally not seen in patients with VSDs 10.
Classification according to location
- membranous/perimembranous (most common: 80-90%)
- including the Gerbode defect
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.
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- 6. Goo HW, Park IS, Ko JK et-al. CT of congenital heart disease: normal anatomy and typical pathologic conditions. Radiographics. 2003;23 Spec No : S147-65. doi:10.1148/rg.23si035501 - Pubmed citation
- 7. Entezami M, Albig M, Knoll U et-al. Ultrasound Diagnosis of Fetal Anomalies. Thieme. (2003) ISBN:1588902129. Read it at Google Books - Find it at Amazon
- 7. Bahtiyar MO, Dulay AT, Weeks BP et-al. Prenatal course of isolated muscular ventricular septal defects diagnosed only by color Doppler sonography: single-institution experience. J Ultrasound Med. 2008;27 (5): 715-20. J Ultrasound Med (full text) - Pubmed citation
- 8. Axt-fliedner R, Schwarze A, Smrcek J et-al. Isolated ventricular septal defects detected by color Doppler imaging: evolution during fetal and first year of postnatal life. Ultrasound Obstet Gynecol. 2006;27 (3): 266-73. doi:10.1002/uog.2716 - Pubmed citation
- 9. Rojas CA, Jaimes C, Abbara S. Ventricular septal defects: embryology and imaging findings. J Thorac Imaging. 2013;28 (2): W28-34. doi:10.1097/RTI.0b013e31824b5b95 - Pubmed citation
- 10. Minette MS, Sahn DJ. Ventricular Septal Defects. Circulation. 114 (20): 2190. doi:10.1161/CIRCULATIONAHA.106.618124 - Pubmed
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