TYK83
Which of the following is associated with a large (non-restrictive) VSD?
A. Right atrial enlargement
B. Right ventricle enlargement
C. Left atrial enlargement
D. Right bundle branch block
Answer
The answer is C. The RIGHT side does not enlarge because the flow is in ventricular systole in which the RIGHT ventricle only acts as a conduit for the increased pulmonary blood flow, not a holding tank. The RIGHT side never really sees increased volume (end-diastolic) and therefore does not dilate. This is also why closure of the VSD results in an INCREASED afterload for the RIGHT side and may result in RIGHT ventricular failure. Before closure, the LEFT ventricle has been helping to eject the blood through the pulmonary artery via the large VSD. Without this help, any increase in PVR (remember these patients are at risk of PVOD and PHTN due to increased PBF) may be too much for the RIGHT ventricular and spell disaster for you as the unlikely person in the room. The only exception to this is if the patient develops severe pulmonary hypertension prior to closure. This may cause RIGHT sided dilation, but it is not generally the case. Who knew?
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