What is Atrioventricular Septal Defect?

Atrioventricular septal defect or AV canal defect describes three variants of the same congenital heart defects, which are separated into the categories of transitional, partial, and complete. It is a serious group of defects that compromise the walls of the heart and the mitral and tricuspid valves that exist on the left and right sides of the heart between the atria and the ventricles. No matter which variant of the defect is present, it has a high rate of surgical success with early detection. There is no recovering from AV canal without surgery and the defects can eventually be fatal without intervention.

As the heart forms, it creates a solid wall or septum between its left and right sides. When AV septal defect is present, at the center of the wall and above and below it, there are holes in the septum, allowing communication of blood from the left and the right. At the same time, the holes may encompass the direct center of the heart where the mitral and tricuspid valves are present, and in some cases, there is only a single valve that pumps blood from both atria to the ventricles. The term AV canal is descriptive of this.

In transitional atrioventricular septal defect, there is a common AV valve that has developed on the ventricular septum, and it is thus divided by that septum so that there are two valves, with various communicating holes between the left and the right sides of the heart. Partial AV canal also has a distinct, though they’re usually connected, mitral and tricuspid valve, and there are holes in the atrial and ventricular septum. A complete atrioventricular septal defect has the single valve, and multiple connections between the right and left side of the heart.

These varying defects are not always detected at birth. Some of the symptoms of heart problems include loud murmurs, failure to grow, poor eating, tiredness, paleness, cyanosis or blueness especially in the fingernails and toenails, and rapid breathing. These signs are always worthy of attention because some forms of cardiac defects may create lung damage if the defects are not repaired early.

A suspected cardiac defect usually warrants a visit to a pediatric cardiologist. Common tests include x-rays, echocardiograms, and electrocardiograms (EKG). If a cardiologist detects an atrioventricular septal defect, additional tests like cardiac catheterization might be ordered to properly visualize the defects and measure lung resistance.

When this defect is diagnosed, children do require surgery. Surgery can be simple or complex depending on the degree to which the atrioventricular septal defect is complete. It is more difficult to separate a single valve and sometimes this requires valve replacement so that both valves function well. This means other valve replacements are needed as children grow. Surgery also involves patching all of the holes in the septum.

Though such surgeries are complex and are performed between the newborn stage and the age of one or two, success rate, especially at respected pediatric cardiac centers is very high. Success rate for repairs may go down if the condition is undetected for several more years. Even with later detection, repair surgeries often have a good chance of success. Once a successful repair is performed, parents can expect yearly appointments with the cardiologist and they will need to make certain their child prevents bacterial endocarditis by taking antibiotics prior to dental procedures.