ABSTRACT
Atrioventricular septal defects (AVSD) constitute a spectrum of anomalies caused by abnormal development of endocardial cushions. AVSD is characterized by formation abnormalities of the atrioventricular valves, the inferior part of the atrial septum, and the posterior part of the ventricular septum. The interatrial communication is located between the inferior parts of the atrial septum and the bridging leaflets. Complete AVSD involves unrestricted communication between both atria and both ventricles. The ventricular septum may shift to the right or left ventricle, thus creating unbalanced AVSD with one dominant and another hypoplastic ventricle. In incomplete AVSD there is an increased pulmonary blood flow due to the left-to-right shunt. In complete AVSD hemodynamic changes are the sum of an atrial septal defect and a ventricular septal defect. Correction of complete AVSD is performed, mostly as single-stage repair, as ‘two-patch’ or ‘single-patch’ repair.
