How common are heart defects in children?

Congenital heart disease, an abnormality of the structure of the heart—the walls, the valves, or the blood vessels of the heart—occurs in about one in every one hundred live births. It can range from problems that don't more than create a murmur, an abnormal heart sound, to life threatening in the newborn. Approximately 50 percent of children who have heart disease will require some kind of therapy—usually surgery, but not always—to correct it.

Are heart defects in children genetically linked?

The most common heart defects are somewhat genetically linked, but usually it's not a single gene problem. There appears to be a genetic predisposition. So if there's a family history of congential heart disease, then a couple will have a slightly higher risk than average of having a child with congenital heart disease.

There are some diseases which are very definitely linked. There are some heart rhythm abnormalities—specific gene defects have been defined—and they definitely persist in families with as much as a 50 percent risk for every pregnancy. There are others that we call syndromic, there are often multiple problems caused by genetic defects, often chromosomal defects, with a high risk of congenital heart disease.

Heart defects are not the only cause of heart disease in children—what are other causes that might affect children?

There are some diseases that we call acquired diseases where the heart is perfectly normal, but you get an illness that has cardiac effects. Fifty years ago, the most common was rheumatic fever, which followed a strep throat. We don't see that very much today, partly because we've improved our therapy of strep throat, but also for reasons we don't understand.

Other diseases we continue to deal with are diseases that we call cardiomyopathy. There can be a virus which attacks the heart, affecting the heart muscle, which affects the heart function. We don't understand a disease called Kawasaki's syndrome that can present in young children. It causes abnormalities with the coronary arteries, the blood vessels that feed the heart. There are some rhythm problems which appears to be acquired, but probably the underlying cause is with the electrical system of the heart and has been present since birth.

A lot of people are now talking about our concern with obesity and hypertension in young children. I think we're all aware of the obesity epidemic. Although that doesn't cause immediate heart problems, it clearly increases the risk for heart attacks and strokes later on in life. We are concerned that we will see heart attacks at a younger age. Probably not in childhood or adolescence, but we're worried that we're going to start to seeing them not at 50 or 60 but in people's 30s and 40s. So even though it's not a primary problem with children, the origin of it starts in childhood.

Is heart disease in children preventable?

It depends on the kind of heart disease. If we're talking about congential heart disease, it is somewhat preventable, but not completely. We strongly recommend that all women considering a pregnancy—and definitely while they're pregnant—avoid all drugs they don't absolutely have to take. Alcohol clearly causes congenital heart disease. There is some concern that exposure to nicotine can certainly cause small infants with a variety of birth defects. So we encourage women who are considering becoming pregnant or who are pregnant, to abstain from all use of alcohol and tobacco. The other thing is folic administration prior to and during the pregnancy—especially early in the pregnancy. It appears to decrease just the overall risk of birth defects.

What is the range of treatment plans available for children with heart disease at UI Children's Hospital?

The classic for congenital heart disease is some kind of surgical repair. The advances in surgery have been nothing short of dramatic. The first child put on the heart-lung machine for bypass was probably about 50 years ago. But in the last 20 years, the results of surgery have been extraordinarily dramatic, and we can do something for almost all kinds of heart disease.

The other very new therapy is actually repairing defects—especially holes in the heart or narrowing of some of the valves—during a cardiac catheterization. In these are procedures we insert a catheter, a long, thin tube, into the heart under X-ray guidance. We use balloons and stents to open up valves in particular or put in small occluder devices to close small holes. The advantage is obviously a much shorter hospitalization stay. Often those children go home the next day. There's no significant surgical incision that needs to heal, and it's a dramatic improvement in our care of children with congenital heart disease.

Your interest lies in heart defibrillation in children. What does a heart defibrillator do to assist a child with heart disease?

A rare number of children will have the very dangerous rhythm called ventricular fibrillation. We see this in some forms of extremely serious heart disease and in other heart rhythm abnormalities. Often they are genetic. Ventricular fibrillation means the heart has no coordinated beating function. When you see a heart that's fibrillating, it just quivers and it doesn't pump blood, so the rest of the body doesn't get blood. If that rhythm is not corrected in five to 10 minutes by a shock, it is either fatal or the child will suffer significant brain damage. With the improvements in technology, we are now able to implant defibrillators into children, just adults who have had heart attacks and are at risk for the same rhythm abnormality, but because of the heart attacks. The device will detect the ventricular fibrillation within seconds; deliver a shock, usually within about 15 seconds. It's lifesaving for these patients.

Do all children with an irregular heartbeat need a defibrillator?

Absolutely not, this is actually a very rare problem. All of us have some irregularity in our heartbeat. We sometimes sort of feel our heart jump, and you can kind of feel it in your throat, or in your neck, or in your chest. It's usually a very benign problem and requires no therapy at all. It's really the rare child who needs a defibrillator.

Once a child has a defibrillator, will they have this device the rest of his life or is it a step to another heart procedure at a later date?

Again it depends on the reason. Some children who have cardiomyopathy who are at risk for ventricular fibrillation are also candidates for a heart transplant, and sometimes we will use a defibrillator, as a bridge to transplantation. Those children will need it for a short period of time. The patients who have the heart rhythm abnormalities—for the foreseeable future, we are saying that they will need it. If there are advances in either drug therapy or even potentially gene therapy, which to date hasn't been successful, but in the future it may be—then there may be an opportunity to remove the defibrillator. But right now, if we have to put it in for those ventricular fibrillation problems, they will need it for the foreseeable future.

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Diane Atkins, MD

University of Iowa Children's Hospital