VSD in infant

You are examining a 5-week-old infant and hear a systolic murmur at the lower left sternal border. You suspect a ventricular septal defect. The parents are concerned and have several questions. 

Answer the following questions based on this scenario. 

1. What is the cause of a ventricular septal defect?
2. What problems will our baby have due to his VSD?
3. How does the defect create these problems?
4. What diagnostic tests will be ordered?
5. What treatment will our baby need?