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A more indepth look at CHD:

Congenital Heart Defects:

The Imperfect Heart

 

Approximately seventeen days after conception, the first functioning organ, the heart begins to beat in the embryo. After the twenty-seventh day of life, the heart has begun to circulate blood to the body of the embryo. By the thirty-seventh day, the atrial septum has begun to divide into two chambers. By the eighth week of development, the basic structures of the hearts are present and so goes the process of the developing heart. An estimated one out of every thousand children will have a pre-existing heart defect at birth. Congenital heart defects account for at least half of all deaths related to a congenital malformation and an estimated 32,000 babies born every year will have some form of congenital heart defect. Many of us never think of a child being born with a congenital heart defect until it happens to us. The parents question the pregnancy and experience profound guilt. "What is a congenital heart defect? What happened to this perfect human being to make an imperfect heart? Was it something I did or did not do?" These questions plaque parents worldwide, who are living with a child with CHD. Yet, the truth is doctors, scientists, and geneticists still do not know. The enhancement of medical technology has brought knowledge about congenital heart disease to a new understanding, and children with congenital heart defects are now becoming able to lead full and active lives.

Congenital heart defects are the most common congenital malformation in the newborn. A heart defect is considered congenital when the heart or blood vessels close to the heart do not form normally before the birth of the newborn. To date a minimum of thirty-five different documented heart defects that range from mild to severe. Cyanotic heart defects occur when the supply of oxygen needed by the body is insufficient, thus causing a bluish appearance around the lips, hands, and feet. Cyanosis results in the lack of blood flow through the lungs. A stenosis or obstruction may occur anywhere in the heart’s valves, arteries, or veins. "Most heart defects either 1) obstruct blood flow in the heart or vessels near it, or 2) cause blood to flow through the heart in an abnormal pattern. Rarely defects occur in which only one ventricle (single ventricle) is present, or 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" (American Heart Association). Often, more children are born with a heart murmur, which is not detected; however, most are benign. One-third of all heart defects will not require treatment; however, the defects that do require repair may cause residual problems such as a heart rhythm disorder or endocarditis.

The cause of congenital heart defects is still a mystery. Approximately 2-4% of congenital heart defects are thought to be the result due to the presence of an environmental factor, adverse maternal conditions, or tetragenetic influences. Tetragenetic influences are anything that may adversely affect the normal development of the fetus. Some prescription drugs, such as Accutane, over-the-counter remedies, or alcohol have been documented to have some form of connection with the CHD baby. Geneticists found a link among CHD and an abnormality in the chromosomes or some form of chromosomal disorders. Three to five percent of children born with a congenital heart defect have a single or multiple gene disorder, for example Down Syndrome or a deletion of a chromosome. The good news is that after giving birth to a child with a heart defect, there is 2-5% chance of a subsequent child being born with a heart defect. A woman can lower her chance of having a baby with CHD by avoiding exposure to viral infections, such as measles, alcohol, recreational drugs, and all medications unless otherwise prescribed by the doctor.

Congenital heart defects are diagnosed by various means. The physical exam is of the utmost importance. During the physical exam, the doctor auscultates the heart, palpates the major organs, and gets a complete history from the patient’s parent. A murmur found during the auscultation of the heart could signal a cardiac lesion. Doctors use the electrocardiogram to evaluate the heart for possible deficiencies of oxygen delivery to the heart itself. Chest x-rays help determine the size and location of the heart. The x-ray may reveal pneumonia or fluid in the lungs. Blood tests, such as an arterial blood gas, help assess the severity of the congenital heart disease. "One of the most important of all advances in heart treatment was Doppler-echocardiography" (Neil 14). The Doppler-echocardiogram, a valuable asset, since its development relays information about the anatomic detail of the exact problem with the CHD baby. "Doppler-echocardiography is such an extraordinary advance that its full impact is not yet realized" (Neil 25). The echocardiogram evaluates the motion and structure of the heart walls, valvular diseases, and the presence of pericardial fluid. By the eighteenth week of pregnancy, a fetal cardiac ultrasound can detect certain cardiac abnormalities in utero. Cardiac catherzation is essential in determining the exact status of congenital heart defects. A cardiologist trained in pediatric technique in a dedicated pediatric facility should only perform cardiac catherazation. "Regardless of how sophisticated diagnostic test have become, a detailed history and a thorough physical examination remain the key elements of a cardiac evaluation (Cohen 249)."

One type of congenital heart defect found in babies, ventricular septal defects, a hole in the two lower chambers of the heart, occur in approximately 22-25 per 10,000 live births. More than ninety percent of newborns with VSD have an associated chromosome abnormalities, especially in babies with "trisomy 18" (Behrman 1148). Ventricular septal defects vary in size. Small defects with loud murmurs indicate the blood is meeting resistance when shunting from one side of the heart to the other. Small ventricular septal defects usually produce a loud murmur and do not affect the heart. In some defects, the blood flows between the right and left chambers of the heart, because of the size of the opening in the wall of the heart. Often the newborn will not develop a full set of symptoms until several days or weeks after birth. This phenomenon happens because the left to right shunt is interdependent upon the pulmonary resistance and often does not occur until days after the birth of the neonate. Often murmurs are accompanied by a thrill, a purring sensation best felt with placing the hand over the area of the heart. The thrill is produced by the forceful flow of the blood as it tries to cross the VSD. The rapid development of changes in the pulmonary blood vessels is most commonly seen in children with VSD. At the time of these changes the arteries and veins thicken and harden in life. Babies may exhibit symptoms of pulmonary hypertension after changes in the pulmonary blood vessels occur. If not repaired early enough, the pulmonary hypertension will become irreversible, due to pulmonary hypertension; high pressure in the lungs may weaken the heart. If pulmonary hypertension is too great, the only course will be the transplantation of the lungs or special medications that help dilate the arteries in the lungs. Fortunately, for the child with VSD, 30-50% of all VSD's will close spontaneously. The first six months are the best chance for closure of the VSD and approximately twenty percent will close before the child reaches two years of age. Children with VSD may present with cyanosis, often noted during spells of crying or at times of respiratory infections.

Another type of congenital heart defect, pulmonic stenosis occurs when a defective pulmonic valve constricts blood flow resulting in congestion of blood in the lungs. In the heart, the pulmonic valve serves two purposes: to prevent the back flow of blood from the lungs and to control the flow of blood that comes from the right ventricle and enters the pulmonary artery. Pulmonic stenosis may occur because of congenital defects, a tumor, or aneurysm that compresses the pulmonic valve, or may be associated with fetal rubella syndrome. There are three classifications of PS: sub-valvular, valvular, and supra-valvular. The most common, valvular stenosis is found at the level of the pulmonic valve. "In valvular PS, the leaflets may be abnormally thick; there may be only one or two functioning leaflets; or there may be a lack or normal separation of the edges of the valve leaflets (called fusion of the valve commissures). Because the valve leaflets cannot open to their full extent, the right ventricle must pump with greater force to overcome this blockage and ensure adequate blood flow to the lungs" (Tong 1). The incidence of a child having an isolated valvular stenosis is between 8-10%. Pulmonic stenosis, the most common right-sided heart defect, affects the right ventricle of the heart. Pulmonic stenosis may result in right ventricular hypertrophy as the heart tries to compensate and overcome the obstruction. In severe cases of PS, babies may present with severe cyanosis. A chest x-ray may reveal a prominent pulmonary artery with pulmonic stenosis. Mild stenosis may not require treatment, but the child is monitored for complications.

With today’s technology in cardiology, ventricular septal defects are treated with a variety of methods. The first and utmost principal treatment is to give the heart enough time to heal itself. If, after the first year of life, depending on the health of the child, the implementation of other methods may occur. If the child starts to develop congestive heart failure, the child will be treated with Lasix. Lasix, a diuretic, helps the child’s kidneys secrete the fluid off the lungs and heart. Digoxin is given to the child to increase the heart’s ability to contract more proficiently. Vasodilators, another type of medication, decrease pulmonary hypertension in the child’s lungs. Since the discovery of cardiac catheterzation a new understanding of ventricular septal defects has occurred. After the first heart-lung bypass machine was invented, the first successful repair of a ventricular septal defect took place in 1955 by Dr. Walton Lillehei. Twenty percent of all defects require surgical repair. Surgical treatment, such as pulmonary artery banding, open-heart surgery, or cardiac catherization, is done depending on the size and location of the defect. Surgical correction is indicated in children two years or younger if complication results, such as growth retardation, evidence of heart failure, or the development of pulmonary hypertension. With pulmonary artery banding, a band is placed around the pulmonary artery to reduce the flow of blood and the high pressure in the lungs. To prevent complications, open-heart surgery is recommended for children with large septal defects that do not close off. During the open-heart surgery, the doctor will close the defect with a Dacron patch or by suturing. The risk of complications is as low as 1-2% or in children with serious complications as high as 15-20%. During the cardiac catherazation, a large catheter is inserted into the femoral artery in the leg and guided into the child’s ventricle. Once the catheter reaches the defect, the doctors then open up an umbrella-like patch that is made of Decron or Gor-tex inside of the hole. The hearts muscle will grow over the patch and repair the hole gradually. After repair the bloods circulation inside of the heart may revert to normal. Complications from this type of surgery such as heart block are less than two percent.

Treatment of pulmonic stenosis is vital when the child experiences complications. Doctors realize the importance in the treatment is to use the least invasive measure possible. Often the initiation of surgical treatment will be done when the pressure in the right ventricle increases. Balloon valvuloplasty is done similar to heart catherterzation. However, with balloon valvuloplasty, instead of opening a blocked artery, the pulmonic valve is opened. After the insertion of the catheter, it is guided through the heart to the pulmonic artery. The pulmonic artery is stretched open. Once the valve is enlarged the balloon is deflated and the catheter is removed from the body. The first balloon valvuloplasty occurred about 1982 and is now safe and highly effective in the treatment of PS. If the balloon valvuloplasty fails, open-heart surgery is the last option, and the valves will be opened manually. If the valves are too narrow to stretch open, the use of a transannular patch repair is done. In using a transannular patch, a cut is made to open the narrowed area of the pulmonic valve and is roofed using a patch, the part of the pericardium, or synthetic fabric. After undergoing surgical correction, follow-up is needed to reassess the function of the heart.

What are the complications that may result from ventricular septal defect? The types of complications from VSD vary with the severity of the defect from child to child. Often children with a VSD that shunts from left to right have frequent chest colds and some degree of difficulty breathing. Children with large VSD's run a high risk of developing heart failure. Children with VSD may develop Eisenmenger’s Complex, also known as pulmonary hypertension. Eisenmenger’s Complex may occur abruptly in early childhood or develop gradually over the years in children. After a child presents with Eisenmenger’s Complex, closure of ventricular septal defect is no longer helpful. Studies reveal that irreversible pulmonary hypertension can be prevented if the child under goes repair before 2 years of age. There is approximately a 12-13% lifetime risk of developing endocarditis from the VSD; however, this risk decreases with surgical repair of the defect. Another complication that has been found in children with VSD is aortic regurgitation. Aortic regurgitation occurs when the blood that passes through the aortic valve is allowed to back flow and causes congestion in that area of the heart. Children with VSD may also present with congestive heart failure. Children with CHF present with a variety of symptoms: rapid and shallow breathing, excessive sweating, inability to feed well, irritability, restlessness, pneumonia, and failure to grow. Fortunately, with proper medical treatment complications can all but be avoided.

Generally, patients with PS have some of the same complications as children with VSD. However, children with PS differ in the aspect that if the stenosis is severe, they may show right-sided heart failure, with edema present in the upper and lower extremities, abdomen; also the liver becomes tender and enlarges. Serious pulmonic stenosis left unrepaired may result in premature death. Potential complications from the balloon valvuloplasty are as follows: bleeding, infection, blood clots, vessel blockage, bradycardia, or tachycardia. Fortunately, the risk of a life-threatening event is estimated to be found in one out of every 50,000 procedures. "In general, however, a child with isolated PS who has mild or no residual valve obstruction nor leakage after the balloon pulmonary valvoplasty should, as best as we can tell, lead a perfectly normal life in duration and quality" (Tong 4).

The long-term prognosis of VSD and PS is encouraging. After the correct surgical repairs, most continue to lead full and active lives. The only noted problem of the CHD baby after repair is the potential for endocarditis. Before dental and surgical procedures, children with CHD should have prophylactic antibiotics to prevent the bacterial endocarditis. Even after repair of the CHD, the patient should be continuously monitored for any further complications.

In July of this year, I gave birth to my third son. The second day of his short life we learned that he had a congenital heart defect. The fear and the guilt I felt were so profound. The first step that I, like most parents, must resolve is to grieve for the loss of the perfect child and to learn to cope with the defect. The hardest is knowing, that at some point within the year my child may need to have open-heart to repair the defect. Everyday I live with the guilt of not knowing if I could have prevented my son’s heart defects. As I sit with him daily and watch him grow, it is difficult to imagine that my child is imperfect. For every parent that lives with a child born with a congenital heart defect, it is difficult knowing what his child faces in the future. The thought of my baby’s chest being opened scares me. I have found that faith in God and my love for my child helps get me through the day knowing what I must face. Luckily, it gives most of us hope that our children will later on lead full lives.

Although the incidence of a baby being born with of congenital heart defect is rare, the toll that is takes on the family is heartbreaking and stressful. As cardiologists, geneticists, and cardiovascular surgeons perfect the treatment for children living with a congenital heart defect, medical technology is becoming more advanced and the incidence of a child with a congenital heart defect leading an active life increases.

 

Works Cited

Behrman, Richard E. Textbook of Pediatrics. 14th ed. Ed. Robert M. Kliegman, Waldo E. Nelson, and Victor C. Vaugham III, Philadelphia: Saunders, 1992.

Cohen, Lawrence S., Marvin Moser, and Barry Zaret, ed. Yale University School of Medicine: Heart Book.

New York: Hearst, 1992.

"Congenital Cardiovascular Disease." Heart and Stroke A-Z Guide. American Heart Association. 12 Oct. 2000 http://www.americanheart.org/Heart_and_Stroke_A_Z_Guide/conghd.html..

Neil, Catherine A., Edward B. Clark, and Carleen Clark. The Heart of a Child. Maryland: John Hopkins

University, 1992.

Tong, Alan. Pulmonary Stenosis and Balloon Valvuloplasty. Ed. Mona Barmash. 9 May 1997. The Children’s Health Information Network. 13 Oct. 2000.

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