Congenital heart disease covers a wide spectrum from small defects, which may be totally asymptomatic and compatible with a normal lifespan, to more severe forms which require urgent intervention. Many defects are possible, but most defects either obstruct flow of blood in the heart or in vessels near to it or cause blood to take an abnormal route through the heart. More rarely only one ventricle may be present, or the right or left side of the heart has failed to form properly (hypoplastic heart). Significant amounts of blood shunting from right to left without traversing the lungs causes cyanotic congenital heart disease.
The management of congenital heart disease has improved so much over the years that many affected children are now adults. Congenital Heart Disease in Adults is covered in a separate article.
The most common causes of congenital heart disease include:
- Ventricular septal defect.
- Atrial septal defect.
- Patent ductus arteriosus.
- Aortic stenosis.
- Pulmonic stenosis.
- Coarctation of the aorta.
- Atrioventricular canal defect (endocardial cushion defect): variable severity of defects involving the atrial septum, ventricular septum, and one or both of the mitral and tricuspid valves.
- Fallot's tetralogy.
- Transposition of the great arteries.
- Tricuspid atresia: complete absence of the tricuspid valve; an atrial septal defect must be present to maintain blood flow.
- Total anomalous pulmonary venous return: all four pulmonary veins are malpositioned and make anomalous connections to the systemic venous circulation.
- Persistent truncus arteriosus.
- Hypoplastic left heart: the left side of the heart is severely underdeveloped.
- Pulmonary atresia: the pulmonary valve is completely closed and the only source of pulmonary blood flow is a patent ductus arteriosus.
- Ebstein's anomaly.
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- The incidence of congenital heart disease in full-term liveborn infants is between 4 and 9 per 1,000.
- Each year there are about 1.5 million new cases worldwide.
- It is the most common congenital condition diagnosed in newborns.
- The incidence of mothers with congenital heart disease having affected children is between 2.5% and 18%, and the incidence of fathers with congenital heart disease having affected children is between 1.5% and 3.0%. Both figures are significantly higher than for the general population. It is unusual for more than one child in the same family to have congenital heart disease.
- A fetus may be affected during cardiac development by intrauterine infection such as rubella, or drugs and toxins taken by the mother, including lithium and alcohol.
- Some genetic conditions are associated with a higher incidence of congenital heart disease including Down's syndrome, DiGeorge syndrome and Turner's syndrome.
- Maternal diabetes mellitus is associated with an increased incidence of congenital heart disease.
- Maternal phenylketonuria is also associated with an increased incidence and a diet free of phenylalanine should be started before conception to reduce the risk of brain damage and congenital heart disease in the fetus.
- Lack of folic acid during the first trimester is associated with neural tube defects but a link with congenital heart disease has not been established.
The cardiovascular system is complex, as the circulation changes from fetal to infant and there may be transient problems such as patent ductus arteriosus or patent foramen ovale, especially in premature babies.
- Many congenital heart anomalies are now diagnosed before delivery, by detailed antenatal scans, but may present soon after birth. See also the separate article Neonatal Examination.
- Babies born with severe left-sided obstructive lesions: systemic blood flow is dependent on right-to-left blood flow through a patent ductus arteriosus. Closure of the duct soon after birth causes acute, severe cardiovascular collapse requiring immediate cardiovascular resuscitation and prostaglandin infusion. Examples of ductus-dependent congenital heart disease include hypoplastic left heart syndrome, pulmonary atresia, transposition of the great arteries, critical aortic stenosis and interrupted aortic arch.
- Routine child health surveillance in the UK and in other developed countries has ensured that the majority of children with significant disease are diagnosed at an early stage.
- Children who have not been diagnosed before birth may present with:
- Heart murmurs (see separate article Heart Murmurs in Children):
- Not all murmurs are pathological.
- Murmurs heard in the first week to months of life are more likely to be due to congenital heart disease than those discovered in later childhood years.
- Murmurs may not appear until an infant has left hospital, as the pulmonary vascular resistance changes with the closure of the ductus arteriosus. Hence, a child with a ventricular septal defect may have no signs for the first 24 hours, and a child with a hypoplastic left heart may appear healthy until the ductus closes.
- Older children with congenital heart disease tend to squat when they become tired or breathless. This is especially true with cyanotic congenital heart disease and notably associated with it.
Investigation should be preceded by a thorough health and development history of the infant or child as well as a history of the pregnancy, including the mother's health and drug use during the pregnancy, and a family history of cardiac abnormalities.
- Babies developing severe cardiovascular and respiratory distress/collapse require urgent hospital admission, CXR, blood gases, assessment of renal function and electrolytes and assessment of other possible causes of cardiovascular collapse, e.g full infection screen.
- Murmurs arising during the first days or weeks of life should be referred to a paediatrician for assessment.
- The initial investigation of choice is echocardiography. It is non-invasive. It can elucidate both anatomy and flow and will give some indication of the underlying abnormality.
- Cardiac catheterisation may be required in more severe cases to assess the extent of the problem, and prepare for correction of the problem.
- Some children with congenital heart disease will require no specific treatment, but may be at risk of infective endocarditis. Recommendations on the Prevention of Endocarditis are covered in a separate article.
- Acute severe presentations may require immediate resuscitation (see Resuscitation Council guideline for Newborn Life Support at the end of this article) and urgent hospital treatment, including prostaglandin infusion for ductus-dependent lesions.
- If the disorder is severe enough to compromise the circulation and the oxygenation of the blood, or to put a strain on the heart or lungs, then surgical correction or non-surgical intervention, such as balloon valvotomy, may be required.
- In the most severe cases (for example hypoplastic heart), a heart transplant may be required.
- The type and extent of the correction required will depend on the underlying anomaly.
- All forms of congenital heart disease, apart from atrial septal defect, carry a risk of infective endocarditis.
- There may be failure to thrive or just difficulty in joining in games and sports with other children.
- A right-to-left shunt can permit paradoxical embolism that may present with a systemic embolism such as a stroke.
- A left-to-right shunt does not cause cyanosis but the high volume pumped by the right side may result in pulmonary hypertension and, if this builds up and exceeds systemic pressure, the shunt may reverse from right to left. This is called Eisenmenger's complex and it may not develop until the child is an adolescent or adult.
- Cyanosis results in polycythaemia; a haemoglobin value as high as 20 g/dL may cause additional difficulty as the blood is so viscous.
- The prognosis for children with congenital heart disease has improved dramatically over a 20-year period.
- In 1986 60% of deaths from congenital heart disease occurred in the first year of life, whereas in the 1990s the majority of deaths occurred in adults over the age of 20.
- It is predicted that 78% of the babies born with congenital heart disease today will survive into adulthood.
- Although many forms of congenital heart disease are not currently preventable, the avoidance of known risk factors such as drugs and alcohol during pregnancy will help to reduce the risk.
- Vaccination against rubella has reduced the number of children born with rubella syndrome in the last two decades. Reduced uptake of the measles, mumps and rubella (MMR) vaccine could allow the incidence of congenital rubella to increase again.
Further reading & references
- Newborn Life Support, Resuscitation Council UK Guideline (2010)
- Moller JH, Taubert KA, Allen HD, et al; Cardiovascular health and disease in children: current status. A Special Writing Group from the Task Force on Children and Youth, American Heart Association. Circulation. 1994 Feb;89(2):923-30.
- Perloff JK, Warnes CA; Challenges posed by adults with repaired congenital heart disease. Circulation. 2001 May 29;103(21):2637-43.
- Hornberger LK; Maternal diabetes and the fetal heart. Heart. 2006 Aug;92(8):1019-21. Epub 2006 May 12.
- Magee AC, Ryan K, Moore A, et al; Follow up of fetal outcome in cases of maternal phenylketonuria in Northern Ireland. Arch Dis Child Fetal Neonatal Ed. 2002 Sep;87(2):F141-3.
- Bower C, Miller M, Payne J, et al; Folate intake and the primary prevention of non-neural birth defects. Aust N Z J Public Health. 2006 Jun;30(3):258-61.
- Danford DA, Martin AB, Fletcher SE, et alEchocardiographic yield in children when innocent murmur seems likely but doubts linger. Pediatr Cardiol. 2002 Jul-Aug;23(4):410-4.
- Abdurrahman L, Bockoven JR, Pickoff AS, et al; Pediatric cardiology update: Office-based practice of pediatric cardiology for the primary care provider. Curr Probl Pediatr Adolesc Health Care. 2003 Nov-Dec;33(10):318-47.
- Mortality from Congenital Heart Disease, British Heart Foundation's Statistics Website
|Original Author: Dr Richard Draper||Current Version: Dr Colin Tidy||Peer Reviewer: Dr Hannah Gronow|
|Last Checked: 16/05/2012||Document ID: 1626 Version: 24||© EMIS|
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