- Most common congenital heart defect; ~2/1000 live births, usually in conjunction with other heart defects but not uncommon to be isolated
- Not uncommonly associated with genetic abnormalities e.g. Down’s syndrome; Edward’s syndrome; Patau’s syndrome
- The size of the VSD, the pressures in the right and left ventricles and pulmonary resistance will determine the physiological effect of a VSD
- At birth, the pressure difference between the left and right side of the heart are almost equal and so the effect is minimal. With time, the pressure gradient increases and symptoms manifest.
- If there is persistent high pulmonary resistance e.g. in Down’s syndrome, this can further halt the effect of a VSD (therefore patients with Down’s are always screened for heart defects shortly after birth)
- Without increased pulmonary resistance/obstruction, the shunt is left to right.
- This rarely has a significant effect on the right heart (as might be expected); but instead, the increased pre-load returning to the left side of the heart causes symptoms of heart failure
- Only in severe disease, can subsequent pulmonary hypertension cause a right-left shunt
- Small lesions may cause few or no symptoms
- Only sign may be a harsh pansystolic murmur (often loudest in small lesions- may have a palpable thrill)
- Moderate defects may present with increased respiration rate and effort and fatigue, particularly after feeding (exertion for a baby)
- Poor weight gain/failure to thrive (normal length but low weight)
- Echocardiography is the main investigation
- CXR/ECG may also be useful to monitor any heart failure
- Small VSDs may resolve themselves
- Larger defects will require surgery to close them