Atrioventricular Canal Defect, CompleteNancy McDaniel M.D.The heart in this defect has four chambers and four valves. The heart in this defect has four chambers, two normal valves, two valves which are abnormal, and two large holes in the heart. There is a hole in the lower part of the wall between the right and left collecting chambers (primum atrial septal defect). There is a large hole between the right and left pumping chambers (ventricular septal defect). The lung artery (pulmonary) and main artery (aorta) valves are normal. The valves between the collecting chambers and the pumping chambers are very abnormal. The abnormality can be minor with small slits or clefts in the valves or can be severe in which there is only one valve that goes across the whole heart. This defect does require open heart surgery to close the two holes and fix the valve abnormalities. The more abnormal the valve is the harder the surgery is. This defect can occur with Down's syndrome (mongolism) or in children with normal chromosomes.
 Normal Heart  |