In the past, children with left-to-right shunt lesions such as ventricular septal defects and atrioventricular canal defects were palliated with a pulmonary artery band. This prevented injury to the pulmonary vasculature while the child grew to a size where complete repair could be undertaken. With the improvements in surgical technique and critical care, there is a push to do a primary complete repair for these defects at younger and younger ages. These operations should be delayed as long as possible to allow for growth but not so long that there is unnecessary heart failure and medication requirements. The primary aim is to determine the optimal timing for repair of left-to-right shunt lesions such as ventricular septal defects and atrioventricular canals. The secondary aim is to define the criteria for failing medical anti-congestive heart failure therapy. This study will be conducted through a retrospective chart review.