| defect, atrial septal | A hole in the septum, the wall, between the atria, the upper chambers of the heart. Commonly called an ASD. ASDs are a major class of congenital cardiac malformation. (12 Dec 1998) |
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| defect, ventricular septal | Hole in the interventricular septum, the wall between the ventricles (lower chambers of the heart). Commonly called a VSD. VSDs are a common class of heart deformity present at birth (congenital cardiac malformation). (17 Dec 1998) |