300 Longwood Avenue Boston, MA 02115 (617) 355-6000 My Child Has: Septal Defects Programs that treat this condition Adult Congenital Heart Service   Cardiac Surgery Program   Interventional Catheterization Program   Cardiac Psychiatry Program   Cardiology Outpatient Services   What is a septal defect? A septal defect is a defect in one of the two chambers on the left side of the heart dividing from the two chambers on the right. Common defects include atrial septal defect, which affects the two top chambers of the heart, and ventricular septal defect, which affects the lower two chambers of the heart. In the septal defect atrioventricular canal defect, a hole in the heart exists where the wall between the upper chambers joins the wall between the lower chambers. Contact Children's Hospital Boston Cardiovascular Program physicians for a second opinion. The information on this website should not be taken as medical advice, which can only be given to you by your personal health care professional. Copyright © Children's Hospital Boston. All rights reserved.