<prompt> Answer this question truthfullyWhat is cardiac catheterization for ventricular septal defect?  <response>: <reason> 1. The Mayo Clinic recommends cardiac catheterization for all adults and adolescents to quantify the degree of pulmonary vascular obstruction, except in those who clearly appear to have a small VSD.2. Infants suspected of having a large defect should undergo cardiac catheterization in the first year of life which should allow surgical correction prior to the onset of permanent pulmonary vascular obstructive disease. 