Clinical Info: The Heart and Down Syndrome
By: Dr. Langford Kidd Helen B.Taussig
Approximately half of all infants born with Down syndrome have a heart defect. Many of these defects have serious implications and it is important to understand them and how they may adversely affect the child so that we may provide the most appropriate medical care.
What are the most common heart defects in children with Down syndrome?
The most common defects are Atrioventricular Septal Defect (formally called Endocardial Cushion Defect), Ventricular Septal Defect, Persistent Ductus Arteriosus and Tetralogy of Fallot.
What is an Atrioventricular Septal Defect?
An Atrioventricular Septal Defect is caused by a failure of tissue to come together in the heart during embryonic life. This results in a large opening in the center of the heart, with usually a hole between the two pumping chambers (a Ventricular Septal Defect) and between the two collecting chambers (an Atrial Septal Defect) as well as abnormalities of the two atrioventricular valves, the mitral and tricuspid valves. This defect occurs in nearly 60% of the children with Down syndrome who are born with congenital heart disease. In less severe cases, Ventricular Septal Defects and Atrial Septal Defects can also occur separately.
What is Persistent Ductus Arteriosus?
The ductus arteriosus is a channel between the pulmonary artery and the aorta and during fetal life diverts blood away from the lungs. After birth this channel usually closes on the first day of life. If it does not close, it is termed "persistent" and results in an increased flow of blood into the lungs.
What is Tetralogy of Fallot?
This is a term given to a heart condition in which there is both a Ventricular Septal Defect and a narrowing of the passage from the right ventricle to the lungs causing Pulmonary Stenosis. The Pulmonary Stenosis causes the blue blood in the right ventricle to cross the Ventricular Septal Defect into the aorta and produces what is commonly called a "blue baby."
What are the effects of Atrioventricular Septal Defect, Ventricular Septal Defect and Persistent Ductus Arteriosus?
These defects result in increased blood flow going to the lungs as the blood goes through the septal defects or the ductus from the high pressure left heart into the low pressure right heart. This flooding of the lungs results in a buildup of pressure in the pulmonary circulation and this higher pressure and high flow leads to damage to the pulmonary circulation and pulmonary hypertension. In the first few months of life, signs of heart failure may be prominent with rapid breathing and failure to grow and gain weight. Later, progressive damage to the blood vessels and the lungs may result in reversal of the shunt and blueness of the skin (cyanosis).
What is the relationship of heart defects to the respiratory system?
The lungs of children with Down syndrome do not develop as fully as in the general population. Consequently, the growth of blood vessels throughout the lungs is limited. The narrowed arteries of the lungs hold potential for long-lasting damage in the face of increased pressure and flow of blood through the lungs.
How are the defects diagnosed?
Some children with Down syndrome and major heart defects will present with heart failure, difficulty breathing and failure to thrive in the newborn period; however, because in some children the defect may not be at first apparent, it is important that all children born with Down syndrome, even those who have no symptoms of heart disease, should have an echocardiogram in the first two or three months of life.
What is the recommended treatment?
Heart surgery to correct the defects is recommended and it must be done before age five or six months in order to prevent lung damage. Although the complexity of the defects raises the risk of surgery slightly above that of surgery on children without Down syndrome, successful surgery will allow many of the affected children to thrive as well as any child with Down syndrome who is born with a normal heart. There may be residual defects (such as imperfect valves, in cases of Atrioventricular Septal Defect), but their effect on health is often minimal.
What are the guidelines for choosing a hospital?
Look for a medical center in a major metropolitan area which has experience in open heart surgery on infants, and experience in operating on infants with Down syndrome in particular. A hospital which conducts at least 10 such operations a year, with a good survival rate, would be considered an experienced hospital.
What should be considered in selecting a surgical team?
Again, experience, together with the parents' rapport with the physician, should be the determining factor in the choice. It is important that an experienced anesthesiologist be selected, as children with Down syndrome often have airway problems.
SUMMARY
- Congenital cardiac defects occur in up to 50 percent of children with Down syndrome.
- Early diagnosis via echocardiogram is crucial within the first two months of life, even if no symptoms are present.
- The majority of heart defects in children with Down syndrome can be surgically corrected with resulting long-term health improvements.
- Experience and success are the key factors in selecting a hospital and surgical team for heart surgery on infants with Down syndrome.
BOOKS/NEWSLETTERS
"Cardiac Aspects," Marino, B. In: Biomedical Concerns in Persons With Down Syndrome. Pueschel, S. & Pueschel, J. (Eds.) (1992). Baltimore, MD: Paul H. Brooks, pp. 91-103. Available through Paul H. Brookes Publishing Co., P.O. Box 10624, Baltimore, MD 21285- 0624; tel.: (800) 638-3775.
This chapter discusses the importance of early diagnosis and management of cardiac problems in children and adults with Down syndrome. The author discusses developments in pediatric cardiology and surgery, in addition to improved medical care.
"Cardiorespiratory Problems in Children with Down Syndrome," Kidd, L. In: Down Syndrome: Advances in Medical Care. Lott, I. & McCoy, E. (Eds.) (1992). New York, NY: Wiley-Liss, pp. 61-69. Available through Wiley-Liss, 1 Wiley Dr., Somerset, NJ 08875; tel.: (800) 225- 5945.
This chapter provides a brief overview of heart disease in children with Down syndrome and the advances in treatments for such conditions. Due to a high incidence of heart disease in infants with Down syndrome, the author stresses the importance of continued screenings for early diagnosis of cardiac problems.
"Heart Disease and Children with Down Syndrome," Cousineau, A. & Lauer, R. In: Medical & Surgical Care for Children with Down Syndrome: A Guide for Parents. Van Dyke, D., Mattheis, P., Eberly, S. & Williams, J. (Eds.) (1995). Bethesda, MD: Woodbine House, pp. 35-63. Available through Woodbine House, 6510 Bells Mill Rd., Bethesda, MD 20817; tel.: (800) 843-7323.
This chapter discusses the different heart disorders typically associated with Down syndrome and their treatment. Basic information is also provided about how the heart functions, causes and symptoms of heart disease, associated disorders of the heart and circulatory system, treatments and results. The text is written in simple language.
"The Heart" In: Medical Care in Down Syndrome: A Preventive Medicine Approach. Rogers, P. & Coleman, M. (1992). New York, NY: Marcel Dekker, Inc., pp.157-168. Available through Marcel Dekker, Inc., 270 Madison Ave., 4th Floor, New York, NY 10016; tel.: (212) 696-9000.
This chapter discusses the importance of continued careful evaluation for early diagnosis of heart defects common in infants with Down syndrome. The authors provide a brief review of cardiac defects and pulmonary disease and a summary of available cardiac care.
The Heart and Down Syndrome, Kidd, L. & Taussig, H. (1995). New York, NY: National Down Syndrome Society. Available through the National Down Syndrome Society, 666 Broadway, New York, NY 10012; tel.: (800) 221-4602 or (212) 460-9330.
This booklet provides general information about various heart defects that are common in children with Down syndrome. Questions are answered about diagnosis and treatment of abnormalities of the cardiovascular system, in addition to the relationship of heart defects to the respiratory system and guidelines for choosing a hospital and surgical team
About the Author: Professor Director, Division of Pediatric Cardiology Johns Hopkins University
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