Atrioventricular Septal Defect

Atrioventricular septal defect (AVSD) is a congenital cardiac malformation characterized by incomplete atrial and ventricular septa development and abnormalities of the atrioventricular valves (AVVs), resulting in a common or partially separate atrioventricular (AV) orifice. AVSD encompasses a spectrum of defects, ranging from partial to complete forms. Partial AVSD typically presents with an ostium primum atrial septal defect, separate AVVs with a common junction, an inlet ventricular septal defect, and a cleft mitral valve. In contrast, complete AVSD features a common AVV, an ostium primum atrial septal defect, and an unrestricted inlet-type ventricular septal defect.  AVSD accounts for approximately 4% to 5% of all congenital heart defects and is strongly associated with chromosomal abnormalities, particularly trisomy 21 (Down syndrome). The condition is a leading cause of early heart failure in infants. However, long-term outcomes after surgical repair have significantly improved due to advances in diagnostic techniques, surgical strategies, and perioperative care. This course provides a comprehensive overview of AVSD, including its embryology, epidemiology, pathophysiology, clinical presentation, diagnostic evaluation, management strategies, complications, and overall clinical significance.