Septal defect refers to a heart condition that causes an opening between the chambers of the heart. Synonyms for the term septal defect include ventricular septal defect (VSD), atrial septal defect (ASD), and atrioventricular septal defect (AVSD). Other commonly used terms for septal defects include a hole in the heart, heart murmur, and congenital heart defect. In some cases, a septal defect may be referred to by the location within the heart such as the interatrial septum or interventricular septum. Regardless of the terminology used to describe it, septal defect can have serious consequences if left untreated and may require medical intervention such as surgery.