CJ is a 16-year-old high school student who is in the clinic for a sports physical prior to beginning basketball practice. He has no known significant medical history, takes no medications, and has no allergies. Subjective data reveal only that CJ is short of breath earlier than most boys on the team. He attributes this to needing to get into better physical condition. The physical exam is unremarkable except for a grade III systolic murmur heard over the entire precordium. An echocardiogram and cardiac catheterization reveal a ventricular septal defect (VSD) with moderate pulmonary hypertension. 1. A VSD is usually an acyanotic defect. Why is this?
2. What is the mechanism of pulmonary hypertension? What may result if it is prolonged?
3. What other disorders besides VSD can produce a systolic murmur? How can character of the murmur and pattern of radiation be used to differentiate among the etiologic factors?
4. Is it necessary to close a VSD? What are the common complications of untreated VSD?