What is an Atrioventricular Canal (AV canal, endocardial cushion defect) defect?
This heart problem includes an atrial septal defect (ASD) low in the atrium, a ventricular septal defect (VSD) high in the ventricle and a single large common atrioventricular valve instead of two. These problems occur when the center area of the heart does not form correctly. The severity of this heart defect varies, depending on how much of the septum of the heart is missing.
Preparing for the Procedure
Prior to cardiac surgery, this heart defect will be diagnosed with an EKG, a chest- x-ray and an echocardiogram. Some children require cardiac catheterization to measure the pressure in the lungs. This measurement helps determine if high pressure increases the risks of surgery. In addition, blood tests are needed to be sure there is no infection, no problem with clotting and normal electrolytes. A blood test to determine the blood type and compatibility will be performed so blood will be available for the surgery.
During the Procedure
The child will be placed under general anesthesia, and special monitoring IVs will be put in. The chest is entered through the sternum (breastbone). The heart/lung machine is connected. With the heart stopped and empty, the right atrium is opened and the defect is carefully visualized. The holes in the heart are repaired with either one or two patches, depending upon the particular circumstances, and the common valve is separated to function as two valves. The heart is then allowed to fill and start beating. A drainage tube and temporary pacemaker wires are placed, and the chest is closed. Usually, a transesophageal echocardiogram is performed to inspect and verify the adequacy of the repair. The child usually remains on the breathing machine for a few hours (sometimes overnight). When the heart appears stable and strong enough, the child will be allowed to awaken and will be taken off the breathing machine.
After the Procedure
After surgery, the child needs a number of days to recover from anesthesia, the use of the heart-lung bypass equipment and the surgery. Initially, the child will be on a ventilator (breathing machine) and may need support from IV medicines and a temporary pacemaker. Once the breathing tube (endotracheal tube) is out, the main goals are to return to normal activity and encourage the child to eat normally and gain weight.