Ventricular Septal Defect (Child)

​Ventricular septal defect (VSD) is a defect or hole in the wall separating the two pumping chambers (the right and left ventricles) of the heart - see figure 3.1.

VSD is one of more common "hole in the heart" seen, and it can occur in isolation or in combination with other congenital heart defects. Not counting those occurring as part of a complex heart disease, VSD accounts for about 15 - 20% of all congenital heart diseases. VSD can be subclassified according to their location on the ventricular septum into perimembranous, subarterial or muscular types.

Figure 3.1
Diagram of a heart with a ventricular septal defect (VSD) on the left, compared to a normal heart on the right. Hover the mouse pointer over the diagram to see the description. LA - Left Atrium, RA - Right Atrium, LV - Left Ventricle, RV - Right Ventricle.

What Are The Effects of VSD?

Figure 3.2 Blood circulation in a heart with an VSD. Note some red blood now crosses the VSD to mix with the blue blood.	Figure 3.3 Blood circulation in a normal heart. Note that the red and blue bloods do not mix during circulation through the heart.

The effects of now having "extra" blood flowing across the VSD into the right ventricle and subsequently re-circulated into the lungs are:

• The left-sided upper heart chamber (left atrium) and left-sided lower heart chamber (left ventricle) can become dilated to accommodate the extra blood volume returning from the lungs.
• The lungs become more "wet" or even become "flooded" with this extra blood. This can lead to breathlessness.
• The blood pressure in the lungs increases.

The degree at which these effects occur would depend on the size of the VSD and the amount of blood that is re-circulated back to the lungs. This can range from insignificant to severe.