Atrial septal defect (ASD) is a hole in the wall between the two upper chambers of the heart, called the atria. This hole usually does not cause any symptoms or problems in a young child. Over a person’s lifetime, the extra blood crossing the hole goes to the lungs. This can damage the blood vessels of the lungs. Adults who still have a hole are at greater risk of strokes. If very small, an atrial septal defect may not require any treatment. Other defects may need cardiac catheterization or surgery to close or patch the hole.

Atrioventricular canal (AV canal, endocardial cushion defect) is present at birth and includes: An atrial septal defect (ASD) low in the atrium (called a primum ASD) A ventricular septal defect (VSD) high in the ventricle A common atrioventricular valve (instead of two separate valves, the mitral and tricuspid valves) Atrioventricular canal defect occurs when the center of the heart does not form properly. The condition varies in severity. Some infants will only have mild symtoms while others may have difficulty growing and gaining weight.

Congestive heart failure (CHF) is when the heart cannot pump enough oxygenated blood to meet the body's needs. There are many reasons why a child might have congestive heart failure, including diseases of the muscle and, commonly, a congenital heart defect that allows extra blood to go to the lungs.

Double outlet right ventricle (DORV) Is a defect where both the aorta and pulmonary artery are attached to the right ventricle. There is no artery attached to the left ventricle. In a normal heart the pulmonary artery leaves the right ventricle and the aorta leave the left ventricle. When DORV occurs, a ventricular septal defect is always present. This lets the blood from the left ventricle get out the aorta to the body by crossing the hole into the right ventricle.

Extracorporeal membrane oxygenation, also known as extracorporeal life support, is a way to support the heart and/or lungs using a machine. The machine is very similar to the heart-lung bypass machine used for open heart surgery. ECMO is used after cardiac surgery to support the heart. When the heart is too weak or needs to recover from surgery, the machine takes on some of the work. ECMO does not cure the heart, but helps it recover or rest for a period of time. ECMO is only used after all other medical treatments have been tried.

Ebstein’s anomaly of the tricuspid valve is a condition where the position of the tricuspid valve is not correct. The tricuspid valve separates the right atrium and the right ventricle of the heart. The valve has three leaflets and opens and closes to allow blood to flow from one chamber to the next. When the tricuspid valve sits very low, more in the space of the right ventricle, it is called Ebstein’s anomaly. This causes the blood to leak backwards into the right atrium.The low position can cause the right ventricle to be too small to function as the pump to the lungs.

Hypoplastic left heart syndrome (HLHS) is when the structures on the left side of the heart are underdeveloped (hypoplastic) and too small to provide enough oxygen-rich blood for the body. The left ventricle is unable to function effectively and other left heart structures, including the mitral valve, aortic valve and aorta, are also often underdeveloped. This heart defect is often detected while the baby is not yet born. Once born, the baby may appear fine until the patent ductus arteriosus (PDA) closes. At that time, no blood will reach the body and the baby will go into shock and die.

Interrupted aortic arch (IAA) is a problem where the aorta has an absent portion. This keeps the blood from reaching the lower body because the aorta is “interrupted." The absent portion can be anywhere along the top curved part of the aorta. A baby born with IAA may appear okay until the patent ductus arteriosus (PDA) closes after birth. The PDA can provide blood flow to the lower body until it naturally closes within a few hours to days after birth. At that time, no blood will reach the lower body and the infant will go into shock, with no blood reaching the legs, kidneys and intestine.

The ductus arteriosus is a blood vessel that connects the aorta and the pulmonary artery in the fetus. When the blood vessel does not close after birth as it should, the problem is called patent ductus arteriosus (PDA). Left untreated, PDA can cause damage to the blood vessels in the lungs, called pulmonary hypertension. Infants and children may have no symptoms other than a heart murmur. If the PDA is large and allows a lot of blood to flow from the aorta to the lungs, the child may have symptoms of congestive heart failure.

Total anomalous pulmonary venous return (TAPVR) is a heart defect where all (total) of the pulmonary veins do not connect to the left atrium. The pulmonary veins are four blood vessels that bring blood from the lungs to the left atrium (upper chamber) of the heart. Partial anomalous pulmonary venous return (PAPVR) is a heart defect where one or more of a child’s pulmonary veins do not connect normally to the left atrium. When TAPVR or PAPVR occurs, the veins are re-directed to another blood vessel that eventually connects to the heart.