An atrioventricular canal defect: is a problem in the part of the heart that connects the upper chambers (atria) to the lower chambers (ventricles).
There are two types of atrioventricular canal defect: complete and partial.
Complete atrioventricular canal (CAVC) is a severe defect in which there is a large hole in the tissue (the septum)
Atrioventricular Canal Defects
Enlarge+that separates the left and right sides of the heart. The hole is in the center of the heart, where the upper chambers (the atria) and the lower chambers (the ventricles) meet.
As the heart formed abnormally, with this large hole, the valves that separate the upper and lower chambers also developed abnormally. In a normal heart, two valves separate the upper and lower chambers of the heart: the tricuspid valve separates the right chambers and the mitral valve the left. In a child with complete atrioventricular canal, there is one large valve, and it may not close correctly.
As a result of the abnormal passageway between the two sides of the heart, blood from both sides mix, and too much blood circulates back to the lungs before it travels through the body. This means the heart works harder than it should have to, and will become enlarged and damaged if the problems aren’t repaired.
Partial atrioventricular canal is the less severe form of this heart defect. The hole does not extend between the lower chambers of the heart and the valves are better formed. Usually it is necessary only to close the hole between the upper chambers (this hole is called an atrial septal defect, or ASD) and to do a minor repair of the mitral valve. Partial atrioventricular canal is also called atrioventricular septal defect, or AVSD.
In complete atrioventricular canal, the following symptoms may be present within several days or weeks of birth:

  1. blue or purple tint to lips, skin and nails (cyanosis)
  2. difficulty breathing
  3. poor weight gain and growth
  4. heart murmur – the heart sounds abnormal when a doctor listens with a stethoscope

Partial atrioventricular canal causes fewer symptoms and sometimes isn’t diagnosed until the child reaches his or her 20s or 30s, and begins to experience irregular heartbeat (arrhythmia), leaky valves or other effects.
The pediatrician who evaluates the newborn in the hospital might make the diagnosis. Or a primary care pediatrician might notice a murmur and other symptoms and refer the baby to the Cardiac Center.
Diagnosis may require some or all of these tests:

  1. echocardiogram – sound waves create an image of the heart
  2. electrocardiogram (ECG) – a record of the electrical activity of the heart
  3. chest X-ray
  4. pulse oximetry – a non-invasive way to monitor the oxygen content of the blood
  5. cardiac catheterization – a thin tube is inserted into the heart through a vein and/or artery in either the leg or through the umbilicus (“belly button”)

cardiac MRI – a three-dimensional image shows the heart’s abnormalities
Sometimes complete atrioventricular canal is diagnosed on a fetal ultrasound and/or echocardiogram. Our Fetal Heart Program can prepare a plan for delivery and care immediately after birth.
Complete atrioventricular canal often occurs in children with Down syndrome.
Complete atrioventricular canal requires surgery, usually within the first two or three months of life. The surgeon will close the large hole with one or two patches. The patches are stitched into the heart muscle. As the child grows, the tissue grows over the patches.
The surgeon will also separate the single large valve into two valves. The surgeon will reconstruct the valves so they are as close to normal as possible, depending on the child’s heart anatomy.
Partial atrioventricular canal also requires surgery, whether it is diagnosed in childhood or adulthood. The surgeon will patch or stitch the atrial septal defect closed, and will repair the mitral valve or replace it with either an artificial valve or a valve from a donated organ.
ARTERIAL SWITCH: The Arterial Switch Operation is an elegant operation that is also simple in concept. Yet it was only first successfully performed in the late 1970s by Dr.Jatene in Brazil. This was mainly due to the technical difficulty in connecting the coronary arteries to the new aorta. Coronary arteries are the first branches of the aorta, and supply blood to the heart muscle itself.
Surgery is carried out through an opening in the middle of the chest. The heart will have to be stopped temporarily during the operation. So the surgeon will first hook up the patient to the heart-lung machine. The aorta and pulmonary artery are disconnected from their abnormal attachments. Their positions are then “SWITCHED”. The aorta is stitched back to the left ventricle and the pulmonary artery to the right ventricle. A VSD is closed, if present. The coronary arteries are also freed, and connected back to the aorta using very delicate hair-thin sutures. When you consider that the size of these coronary arteries in a new-born is hardly a millimeter, you can imagine the technical skill and expertise that the surgeon must possess to carry out this connection without mishap.
FONTAIN:The Fontan procedure, or Fontan/Kreutzer procedure, is a palliative surgical procedure used in children with complex congenital heart defects. It involves diverting the venous blood from the right atrium to the pulmonary arteries without passing through the morphologic pulmonary ventricle.
The Fontan procedure has more recently been used in pediatric situations where an infant only has a single effective ventricle, either due to heart valve defects (e.g. tricuspid or pulmonary atresia) or an abnormality of the pumping ability of the heart (e.g. hypoplastic left heart syndrome, hypoplastic right heart syndrome), or has complex congenital heart disease where a bi-ventricular repair is impossible or inadvisable.
Children with hypoplastic left heart syndrome have a single effective ventricle supplying blood to the lungs and the body (either from birth or after an initial surgery e.g. Norwood procedure). They are delicately balanced between inadequate blood supply to the lungs (causing cyanosis) and oversupply to the lungs (causing heart failure). In addition, the single ventricle is doing nearly twice the expected amount of work (because it has to pump blood for both lungs and body). As a result, these children can have trouble gaining weight, and are also vulnerable to decompensation in the face of otherwise minor illnesses (even a common cold). Sometimes medications (e.g. diuretics) can help them through this stage.
Therefore, when either they are large enough, and if the pressure in the pulmonary arteries is low enough, these children are referred for Fontan procedure commonly after 2 years of life
There are three different types of Fontan procedure:

  1. Atriopulmonary connection (the original)
  2. Intracardiac total cavopulmonary connection (lateral tunnel)
  3. Extracardiac total cavopulmonary connection

TOTAL CAVO PULMONARY CONNECTION: total cavopulmonary connection (TCPC), anastomoses portion of the caval veins to the pulmonary artery (PA).
In this operation, a “tunnel” is created within the right atrium using an artificial fabric patch. The tunnel links the superior and inferior vena cava (SVC and IVC) to each other. The tunnel is then connected to the pulmonary artery. Because of this, the operation is also called TOTAL CAVO-PULMONARY CONNECTION – or TCPC
The advantage with this technique is that blood flow is laminar, and energy loss due to turbulent flow is least, and thus improving lung blood flow.
Later improvements of the TCPC operation have allowed:

  1. Construction of the tunnel with the patient’s own heart tissue, avoiding use of artificial fabric
  2. Creating the tunnel “outside” the right atrium, avoiding an incision in the atrium
  3. Performance of the operation without using the heart lung machine – almost like a closed heart operation.

VALVE REPLACEMENT: is the replacement of one or more of the heart valves with either an artificial heart valve or a bioprosthesis (homograft from human tissue or xenograft e.g. from pig). It is an alternative to valve repair.
There are four procedures:

  1. Aortic valve replacement
  2. Mitral valve replacement
  3. Tricuspid valve replacement
  4. Pulmonary valve replacement

CONDUIT REPAIR:Many repair operations for congenital heart defects involve the replacement of valves and/or the insertion of conduits (basically tubes) to redirect blood flow. Most surgically implanted valves or conduits will last 10-20 years before they wear out, become obstructed, or lose efficiency. When their function becomes impaired for any of these reasons, replacement becomes necessary.
Implanted conduits may be made of pericardium (from the sac-like membrane that envelopes the heart), human or bovine pulmonary arteries or aortas, Dacron®, or Goretex®. Metallic conduits are no longer used in the pulmonary circulation because of the risk of thrombosis (clot formation). In some cases, conduits may be supported by internal stents.
Before a valve or conduit replacement operation is attempted, the condition of the pulmonary and coronary arteries will need to be determined. (The pulmonary arteries carry blood from the heart to the lungs; the coronary arteries carry blood from the aorta to the heart muscle itself.) Sometimes, the deterioration of the valve or conduit occurs in conjunction with changes in these vessels, or in other areas, which may also need modification.