Ventricular septal defect

A ventricular septal defect (VSD) is a defect in the interventricular septum allowing a haemodynamic communication between the right and left ventricles. It typically results in a left to right shunt.

Epidemiology

One of the most common congenital cardiac anomalies and be associated with up to 40% of such anomalies 1. A VSD can occur on its own but frequently tends to occur with other cardiovascular associations.

Cardiovascular associations

  • tetralogy of Fallot
          • truncus arteriosus
          • double outlet right ventricle (including Taussig-Bing malformation)
          • aortic coarctation
          • tricuspid atresia
          • aortic regurgitation
          • pulmonary stenosis

Classification according to location

  • membranous (most common : ~ 90%)
          • inlet
          • outlet
          • muscular / trabecular

Radiographic features

Plain film

CXR 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 oedema, pleural effusion or / and increased pulmonary vascular markings.

Ultrasound / Echocardiography

Direct visualisation of septal defect on four chamber view. A perimembranous VSD can seen as a septal dropout in the area adjacent to the tricuspid septal leaflet and below the right border of the aortic annulus.

CT

Allows direct visualisation of defect on contrast CT.

MRI

May also show added functional information (e.g. quantifiation / shunt severity) in addition to anatomy. Some muscular defects can give a "Swiss cheese" appearance owing to their complexity.

Complications

* Eisenmenger phenomenon with shunt reversal ( i.e. L > R becomes R > L )
* cardiac failure

vsd.jpg

View of the right side of the heart with numerous VSDs. From Wikimedia

vsd%20xray%201.jpg

VSD X-ray

vsd%20echo.jpg

VSD Echo

vsd%20xray%203.jpg

VSD (small) X-ray

Article Author : Dr Yuranga Weerakkody, Radiopaedia

References

* 1. Barboza J et.al. Prenatal Diagnosis of Congenital Cardiac Anomalies: A Practical Approach Using Two Basic Views, RadioGraphics 2002; 22:1125–1138
* 2. Christian J. Kellenberger, Cardiovascular MR Imaging in Neonates and Infants with Congenital Heart Disease, RadioGraphics, Jan 2007 27, 5-18
* 3. Udo Sechtem, Ventricular Septal Defect: Visualization of Shunt Flow and Determination of Shunt Size by Cine MR Imaging, AJR 149:689-692, October 1987
* 4. Jaffe et.al. Supracristal Ventricular Septal Defects: Spectrum of Associated Lesions and Complications, AJR 128:629-637, April 1977
* 5. Wang et.al, Cardiovascular Shunts: MR Imaging Evaluation, RadioGraphics, 23, S181-S194 2003 Oct
* 6. Hyun Woo Goo et al ,CT of Congenital Heart Disease: Normal Anatomy and Typical Pathologic Conditions, October 2003 RadioGraphics, 23, S147-S165.

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