A new study, presented today at the AATS 101st Annual Meeting, shows an association between decreased survival at five years and leaving an atrial communication at biventricular repair of unbalanced AVSD after adjusting for other known risk factors. During repair of atrioventricular septal defect (AVSD), surgeons may leave an atrial level shunt when they have concerns about postoperative pulmonary hypertension, a hypoplastic right ventricle (RV), hypoplastic left ventricle (LV), or as part of their routine practice. The study sought to determine factors associated with mortality after biventricular repair of AVSD.