Atrioventricular canal defect is a combination of heart problems resulting in a defect in the center of the heart. The condition occurs when there's a hole between the heart's chambers and problems with the valves that regulate blood flow in the heart. The condition is often associated with Down syndrome. Atrioventricular canal defect allows extra blood to flow to the lungs. Untreated, atrioventricular canal defect can cause heart failure and high blood pressure in the lungs.
AV canal defects, also known as atrioventricular septal defects or endocardial cushion defects, account for about 5% of all congenital heart disease and are most common in infants with Down syndrome (15%–20% of all newborns with Down syndrome have atrioventricular canal defects).
Patients with incomplete atrioventricular septal defects (AVSDs) present with signs and symptoms similar to those of secundum atrial septal defects (ASDs) and, as such, rarely require medical therapy. Medical therapy in patients with complete atrioventricular septal defects consists of aggressive anticongestive treatment for the signs and symptoms of congestive heart failure (CHF). The mainstays of medical therapy are furosemide (for diuresis for the volume-overloaded heart), digoxin (as a mild inotrope), and ACE inhibitors (for afterload reduction).