What is Conginetal Heart or Blood Vessel Defect?
Congenital means inborn or existing at birth. Among the terms you may hear are congenital heart defect, congenital heart disease andcongenital cardiovascular disease. The word“defect” is more accurate than “disease.” Acongenital heart defect occurs when the heart or blood vessels near the heart don’t develop normally before birth.

Congenital heart defects are present in almost one percent of live births. They’re the
most common congenital malformations in newborns. In most cases scientists don’t
know why they occur. Sometimes a viral infection causes serious problems. German
measles (rubella) is an example. If a woman contracts German measles while pregnant, it can interfere with how the baby’s heart develops or produce other malformations. Other viral diseases also may cause congenital defects.

Heredity sometimes has a role in congenital cardiovascular defects. More than one child in a family may have a congenital cardiovascular defect, but this is rare. Certain conditions affecting multiple organs, such as Down’s syndrome, can involve the heart, too. Some prescription drugs and over-the-counter medicines, as well as alcohol and “street” drugs, may increase the risk of having a baby with a heart defect. Researchers are studying other factors.

What are the types of Congenital defects?
Most heart defects either obstruct blood flow in the heart or vessels near it, or cause
blood to flow through the heart in an abnormal way. Rarely defects occur in which only one ventricle (single ventricle) is present, or both the pulmonary artery and aorta arise from the same ventricle (double outlet ventricle). A third rare defect occurs when the right or left side of the heart is incompletely formed (hypoplastic heart). Several congenital defects of each type are described here.

Patent ductus arteriosus (PDA)
This defect lets blood mix between the pulmonary artery and the aorta. Before birth there’s an open passageway (the ductus arteriosus) between these two blood vessels. Normally this closes within a few hours of birth. When this doesn’t happen, some blood that should flow through the aorta and on to nourish the body returns to the lungs. A ductus that doesn’t close is common in premature infants but rare in full-term babies.







Obstruction defects
An obstruction is a narrowing that partially or completely blocks the flow of blood. Obstructions called stenoses can occur in heart valves, arteries or veins. The three most common forms of obstructed blood flow are pulmonary valve stenosis, aortic valve stenosis and coarctation of the aorta. In pulmonary stenosis (PS) the pulmonary
or pulmonic valve is defective and doesn’t open properly. This valve is between the right ventricle and the pulmonary artery. Normally it opens to let blood flow from the right ventricle to the lungs. A defective pulmonary valve that doesn’t open properly is called stenotic. This forces the right ventricle to pump harder than normal to overcome the obstruction. In aortic stenosis (AS) the aortic valve, between the left ventricle and the aorta, is narrowed. The heart has difficulty pumping blood to the body. Aortic stenosis occurs when the aortic valve didn’t form properly. A normal valve has three leaflets (cusps) but a stenotic valve may have only one cusp (unicuspid) or two cusps
(bicuspid), which are thick and stiff. In coarctation of the aorta (“Coarct”) the aorta is pinched or constricted. This obstructs blood flow to the lower body and increases blood pressure above the constriction.


Septal defects
Some congenital heart defects let blood flow between the heart’s right and left chambers. This happens when a baby is born with an opening between the wall (septum) that separates the right and left sides of the heart. This defect is sometimes
called “a hole in the heart.”

The two most common types of such openings are atrial septal defect and ventricular septal defect. Two variations are Eisenmenger’s complex and atrioventricular canal defect.

In atrial septal defect (ASD) an opening exists between the heart’s two upper chambers. This lets some blood from the left atrium (blood that’s already been to the lungs) return via the hole to the right atrium instead of flowing through the left ventricle, out the aorta and to the body.

In ventricular septal defect (VSD), an opening exists between the heart’s two lower chambers. Some blood that’s returned from the lungs and been pumped into the left ventricle flows to the right ventricle through the hole instead of being pumped into the aorta. Because the heart has to pump extra blood and is overworked, it may enlarge.

Eisenmenger’s complex is a ventricular septal defect coupled with pulmonary high blood pressure, the passage of blood from the right side of the heart to the left (right to left shunt), an enlarged right ventricle and a latent or clearly visible bluish discoloration of the skin called cyanosis. It may also include a malpositioned aorta that receives ejected blood from both the right and left ventricles (an overriding aorta). A less-common type of opening is the atrioventricular (AV) canal defect, also called endocardial cushion defect or atrioventricular septal defect. A large hole in the center of the heart exists where the wall between the upper chambers joins the wall between the lower chambers. Also, the tricuspid and mitral valves that normally separate the heart’s upper and lower chambers aren’t formed as individual valves. Instead, a single large valve forms that crosses the defect.


Cyanotic defects
Another type of heart defect is congenital cyanotic heart defects. In these defects, blood pumped to the body contains less oxygen than normal. This causes a condition called cyanosis, a blue discoloration of the skin. The term “blue babies” is often applied to infants with cyanosis.

Examples of cyanotic defects are tetralogy of Fallot, transposition of the great arteries,
tricuspid atresia, pulmonary atresia, truncus arteriosus and total anomalous pulmonary venous connection.

Tetralogy of Fallot has four components. The two major ones are a large hole, or ventricular septal defect, that lets blood pass from the right to the left ventricle without going through the lungs; and a narrowing (stenosis) at or just beneath the pulmonary valve. This narrowing partially blocks the blood flow from the heart’s right side to the lungs. The other two components are the right ventricle is more muscular than normal; and the aorta lies directly over the ventricular septal defect.


In transposition of the great arteries, the positions of the pulmonary artery and the aorta are reversed. The aorta is connected to the right ventricle, so most of the blood returning to the heart from the body is pumped back out without first going to the lungs. The pulmonary artery is connected to the left ventricle, so most of the blood returning from the lungs goes back to the lungs again.

Infants born with transposition survive only if they have one or more connections that let oxygen-rich blood reach the body. One such connection may be an atrial septal defect or a ventricular septal defect. Another may be a patent ductus arteriosus (PDA).

In tricuspid atresia, there’s no tricuspid valve. That means no blood can flow from the
right atrium to the right ventricle. As a result, the right ventricle is small and not fully developed. The child’s survival depends on there being an atrial septal defect and usually a ventricular septal defect. Because the circulation is abnormal, the blood can’t get enough oxygen, and the child looks blue (cyanotic).

In pulmonary atresia, no pulmonary valve exists, so blood can’t flow from the right ventricle into the pulmonary artery and on to the lungs. The right ventricle acts as a blind pouch that may stay small and not well developed. The tricuspid valve is often poorly developed, too.

An opening in the atrial septum lets blood exit the right atrium. That allows venous (bluish) blood to mix with the oxygen-rich (red) blood in the left atrium. The left ventricle pumps this mixture of oxygen-poor blood into the aorta and out to the body. The baby appears blue (cyanotic) because there’s less oxygen in the blood circulating through the arteries. The only source of lung blood flow is the patent ductus arteriosus (PDA). If the PDA narrows or closes, the lung blood flow is reduced to critically low levels. This can cause very severe cyanosis.

Truncus arteriosus is a complex malformation where only one artery arises from the heart and forms the aorta and pulmonary artery. Surgery for this condition usually is required early in life. It includes closing a large ventricular septal defect within the heart, detaching the pulmonary arteries from large common artery, and connecting the pulmonary arteries the right ventricle with a tube graft. Children with truncus arteriosus need lifelong follow-up to see how well the heart is working.

Total anomalous pulmonary venous (P-V) connection is another cyanotic defect. The pulmonary veins that bring oxygen-rich (red) blood from the lungs back to the heart aren’t connected to the left atrium. Instead, the pulmonary veins drain through abnormal connections to the right atrium. In the right atrium, oxygen-rich (red) blood from the pulmonary veins mixes with venous (bluish) blood from the body. Part of this mixture passes through the atrial septum (atrial septal defect) into the left atrium. From there it goes into the left ventricle, to the aorta and out to the body. The rest of the poorly oxygenated mixture flows through the right ventricle, into the pulmonary artery and on to the lungs. The blood passing through the aorta to the body doesn’t have enough oxygen, which causes the child to look blue (cyanotic).

How does a doctor detect a heart defect?
Serious congenital heart defects are usually diagnosed at birth or during infancy. Sometimes a doctor hears an abnormal sound (a murmur) in the heart. In other babies, cyanosis is present.

Special tests are often needed. A chest X-ray gives information about a child’s lungs and the heart’s size and shape. An electrocardiogram (ECG or EKG) can show an abnormal heartbeat rhythm.

A Doppler echocardiogram is also usually used. An echocardiogram is a painless test that uses high-frequency sound waves to image the heart’s internal structures. A Doppler test uses sound waves to measure blood flow. By combining these two tests, a doctor can learn about the heart’s structure and function.

Sometimes an in-hospital test called a cardiac catheterization is required. Here a doctor inserts a catheter into a blood vessel in the groin and slowly advances it under X-ray guidance until it reaches the heart. This test can measure blood pressure and how much oxygen is in the blood of the heart chambers.

Some congenital heart defects don’t require surgery. Drugs may be used to prevent complications, relieve symptoms or both. Sometimes medical treatment is used for awhile and surgery performed later.

How can a Congenital Heart defect be treated?
Many children with congenital heart and blood vessel defects may need medical treatment such as diuretics, digoxin or other drugs. Diuretics help the body excrete water and salts by promoting urination. Digoxin strengthens the heart’s contractions, slows the heart rate and helps remove extra fluid from body tissues.

Some children may need surgery. The goal of surgery is to repair the defect as completely as possible and make circulation as normal as possible. Some children may need more than one surgical procedure.

The malformed part of the heart or blood vessel may be surgically repaired in several
ways. Here are some examples:

• A ductus arteriosus can be closed by tying it.
• Stenotic valves can be widened, either by a balloon procedure during cardiac catheterization or by surgery.
• A narrowed segment of a blood vessel can be removed.
• Septal defects can be closed by sewing the defect shut or by sewing a patch (made of durable, synthetic material) over the hole.
• In babies with transposition of the great arteries, the major arteries can be switched.
• A shunt can be used to form a passage between blood vessels to divert blood from one part of the heart to another.
• In some cases, treatment with special equipment in the cardiac catheterization
  laboratory is effective.
  

Most people with congenital heart defects, before and after treatment, are at risk for getting an infection on the heart’s inner lining, valves or blood vessels (endocarditis). To help prevent this, they’ll need to take antibiotic drugs before certain dental and surgical procedures.