Surgical anatomy of the atrioventricular septum and atrioventricular septal defects

SummaryDefects of the atrioventricular septum impose changes in the septal architecture, atrioventricular valves, and conduction system that must be well understood for optimal repair. The atrioventricular node and bundles are shifted to more posterior and inferior positions that can be anticipated by the surgeon so as to maintain the integrity of atrioventricular conduction. The atrioventricular valve is a five leaflet structure that possesses a common orifice or separate orifices depending on characteristics of the superior and inferior bridging leaflets. These features are demonstrated by intraoperative photographs viewed from the surgeon's position.