congenital heart defects

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حسين عباس جار الله اللامي
4/21/2011 12:00:00 AM

Congenital Heart Defects



Truncus arteriosus


This is a defect in which the normally separate pulmonary artery and aorta merge into one single large vessel (truncus) arising from the two bottom chambers of the heart (right and left ventricles). Many people who have this defect also have a large ventricular septal defect, which turns the right and left ventricles into a single chamber. This allows red oxygenated blood and blue unoxygenated blood to mix. Too much blood may flow to the lungs, flooding them and making it difficult to breathe. It can also result in life-threatening pulmonary hypertension — high blood pressure in the lungs.


Surgery is needed to close the septal defect with a patch and to separate the pulmonary arteries from the trunk.


Hypoplastic left heart syndrome


In this condition found in babies, the left side of the heart is underdeveloped (hypoplastic), including the aorta, aortic valve, left ventricle and mitral valve. As a result, the baby s body doesn t receive enough oxygen. In the first few days after a baby is born, the ductus arteriosus remains open (patent), allowing normal blood flow. But when the ductus arteriosus naturally closes, signs and symptoms begin, including a bluish cast to the skin from lack of oxygen (cyanosis), difficulty breathing and being unable to feed.


Hypoplastic left heart syndrome is sometimes found during ultrasound exams before a baby is born. Treatment options for this life-threatening condition are a heart transplant or a multistage surgical procedure done during the first few years of life.


Atrioventricular canal defect


This is a combination of defects, including a large hole in the center of the heart and a single common valve instead of the separate tricuspid and mitral valves. Also called atrioventricular septal defect, this defect is classified by whether it s only partial (involving only the upper chambers of the heart), or complete (in which blood can travel freely among all four chambers of the heart). Both forms of the defect allow extra blood to circulate to the lungs, causing the heart to enlarge.


The condition occurs most often in children with Down syndrome. Infants may also have trouble breathing and not grow well. Surgery is often done in infancy to close the hole and reconstruct the valves.




Ebstein s anomaly


This is a defect of the tricuspid valve, which controls blood flow between the heart s right atrium, which is an upper chamber of the heart, and the right ventricle, a bottom chamber of the heart. The valve is positioned lower than normal into the right ventricle instead of remaining between the atrium and the ventricle. The incorrectly formed ventricle is too small and the atrium too large, and neither functions properly. The valve often allows blood to leak from the ventricle into the atrium. This defect often occurs along with other heart defects.


Some patients have symptoms early in life including heart failure and life-threatening irregular heartbeats (arrhythmias). Other patients may have no signs or symptoms until adulthood. Treatment is with medications or with surgery.


Tetralogy of Fallot


This defect is a combination of four (tetralogy) heart defects. The four defects typically are ventricular septal defect (VSD), pulmonary valve stenosis, a misplaced aorta and a thickened right ventricular wall (right ventricular hypertrophy). They usually result in an insufficient amount of oxygenated blood reaching the body.


Complications of tetralogy of Fallot include cyanosis — sometimes called "blue baby syndrome," since the lips, fingers and toes may have a bluish tinge from lack of oxygen — as well as poor eating, not being physically able to exercise, irregular heartbeats (arrhythmias), delayed growth and development, and stroke. Surgery to repair the defects is required early in life.


Transposition of the great arteries


With this defect, the positions of the aorta — the main artery leading away from the heart — and the pulmonary artery, which leads to the lungs, are reversed (transposed). The aorta and pulmonary arteries are, together, sometimes referred to as the great arteries. The aorta arises from the right ventricle instead of the left ventricle. The pulmonary artery also arises from the left ventricle instead of the right. This prevents nourishing oxygenated blood from reaching the body.


This condition would quickly be fatal to a newborn except it s generally accompanied by another defect — commonly a septal defect or patent ductus arteriosus — that allows oxygen-rich blood to get to the body. Surgery to repair the condition is usually necessary shortly after birth.


Coarctation of the aorta


This is a narrowing (coarctation) in a portion of the heart s main artery (aorta). Coarctation forces the heart to pump harder to get blood through the aorta and on to the rest of the body.


Coarctation of the aorta can cause several life-threatening complications, including severe high blood pressure, a bulge in the aorta that can burst (aortic aneurysm), infection of the heart (endocarditis), brain hemorrhage, stroke, heart failure and premature coronary artery disease. Repair is typically recommended before age 10, either by surgically removing the affected portion or widening it through a surgical procedure called balloon angioplasty and placement of a mesh tube that can hold the aorta open (stent).


Aortic stenosis


Aortic stenosis is a defect that narrows or blocks the aortic valve opening, making it difficult for the heart to pump blood into the aorta — the main artery leading away from the heart — on to the rest of your body.


The defect can cause the heart to get bigger, left-sided heart failure, abnormal heart rhythms (arrhythmias), infections of the heart (endocarditis) and fainting. Treatment includes surgery to repair or replace the valve or, in young children, widening of the valve through a surgical procedure called balloon valvuloplasty, in which a balloon-like device widens the valve so that blood can flow through.


Pulmonary valve stenosis


In this condition, blood flow from one of the heart s bottom chambers, the right ventricle, to the pulmonary artery is slowed by narrowing at the pulmonary valve. When there s narrowing (stenosis), the right ventricle must pump harder to get blood into the artery that carries blood to the lungs (pulmonary artery). Pulmonary valve stenosis may occur along with other defects, such as thickening of the muscle of the right ventricle below the valve.


In many cases, pulmonary stenosis is mild and doesn t require treatment. But because it can cause heart failure, arrhythmias or enlargement of the right heart chambers, it may be necessary to correct the defect. In many cases a balloon (pulmonary valvuloplasty) open the narrowed valve. In some cases, especially people with other heart defects, surgery may be necessary to replace the diseased valve with an artificial valve.


Patent ductus arteriosus


Before birth, a blood vessel called the ductus arteriosus connects the pulmonary artery — the artery carrying blood to your lungs — and the aorta, the large artery that carries blood away from the heart. Before a baby is born, the ductus arteriosus allows blood to bypass the lungs because the baby receives oxygen through the placenta and umbilical cord. The ductus arteriosus normally closes within soon after birth. If the ductus arteriosus remains open (patent), some blood that should flow through the body goes to the lungs.


This defect can cause heart failure or an infection of the heart (endocarditis). In infants, it can be closed with medications. In older children and adults, surgery is performed to close the vessel.


Atrial septal defect


Atrial septal defect is a hole that occurs when the muscular wall (septum) separating the top two chambers of the heart (right and left atria) doesn t close properly. This allows oxygen-rich blood from the left atrium to flow into the right atrium, where it mixes with blood that doesn t have adequate oxygen in it. Blood from the left atrium should normally flow into the left ventricle and on to the aorta and the rest of the body.


Minor cases may cause no symptoms and may not require treatment. Larger defects may require surgery or cardiac catheterization to repair the hole.


Ventricular septal defect


Sometimes called a hole in the heart, this defect — the most common congenital heart defect — occurs when the muscular wall (septum) separating the bottom chambers of the heart (right and left ventricles ) doesn t fully form. The hole allows oxygen-rich blood to leak from the left ventricle into the right ventricle, instead of moving into the aorta and on to the body. In the right ventricle, the oxygen-rich blood mixes with blood that doesn t have enough oxygen in it.


Ventricular septal defect can lead to heart failure, high blood pressure in the lungs (pulmonary hypertension), infections of the heart (endocarditis), irregular heartbeats (arrhythmias) and delayed growth. Small holes may heal on their own or cause no symptoms. Larger holes may require surgery to stitch the hole closed or to cover the hole with a patch.


At the current time, prenatal heart surgery and catheterization (balloon procedures) is limited to a small number of conditions and the effectiveness has not been proven.

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