In many infants, heart defects can be definitively corrected
through surgical repair or the use of devices delivered through
catheterization. This section provides a brief review of commonly
used techniques for the correction of congenital heart defects. Table 122A-5.1 lists common surgical procedures
used in the treatment or palliation of congenital heart defects.
of Congenital Heart Defects
Arrhythmias may be caused by the underlying lesion, the surgical
repair, or digitalis toxicity. Supraventricular tachycardia is common
with procedures that employ atriotomy (Senning operation, Mustard
operation, Fontan procedure, ASD repair, TAPVR repair). Bradycardia
may occur in patients who have undergone the Fontan procedure, and
AV block is not uncommon after AV canal repair.
Some lesions recur after surgery. This is most commonly seen
with coarctation of the aorta, which recurs in 10% of cases.
Pulmonary stenosis and aortic stenosis balloon dilation may also
be complicated by restenosis or valvular incompetence.
When palliative shunt procedures are performed in the neonatal
period prior to definitive operative repair of complex congenital
heart disease, shunts can malfunction. Typically, infants with surgical
shunt failure develop acute distress with increasing cyanosis when
the shunt flow narrows to <50% of usual. Ordinarily,
a continuous murmur should be heard over the shunt. Diminution or disappearance
of the murmur suggests occlusion of the shunt. Typically, emergency
physicians can do nothing for these infants. Palliative therapy with
100% oxygen is used, and transfer to a tertiary center
is expedited. The use of thrombolytic therapy has been attempted,
but thrombolytic agents should be administered by a pediatric cardiologist
either directly into the shunt or systemically. In all cases, definitive
treatment consists of surgical repair.
Many children with congenital heart disease have increased pulmonary
artery pressure, particularly those with large VSDs. Pulmonary vasospasm
can develop in response to painful procedures. In such conditions,
cyanosis and lethargy can develop and can mimic the hypercyanotic
episodes of TOF. Treatment is administration of 100% oxygen
to facilitate pulmonary vasodilation and consideration of alkalinization
with IV sodium bicarbonate, 1 mEq/kg. Anxiolysis and analgesia
Because dosing of diuretic medications is weight based, normal
infant growth may lead to inadequate diuretic therapy that presents
as CHF. Conversely, during times of excess fluid losses, such as
from diarrhea or vomiting, dehydration can occur with hemoconcentration
that can compromise cardiac function or shunt integrity. Electrolyte
imbalances are a common side effect of many diuretics and can be
exacerbated during intercurrent illness, so potassium levels should
always be checked.
Because of digoxin’s narrow therapeutic window, digoxin
toxicity can easily develop. In infants, toxicity often presents with
bradycardia or other dysrhythmias. The usual adult patterns of atrial
and ventricular tachycardia are not seen in younger children, although they
may occur in adolescents. It is always good practice to monitor digoxin
concentrations expectantly during any visit at which blood is drawn.
Usually, increased serum concentrations can be managed by withholding
dosages of digoxin. Rarely, pharmacologic intervention is required
for bradycardias. Ventricular dysrhythmias are managed medically
with lidocaine or phenytoin. For severely intoxicated children,
the use of digoxin immune globulin (Digibind) is indicated and reverses
toxicity rapidly. Usually, the dosage can be calculated readily
based on the amount of digoxin elevation in nanograms above the
normal level (see Chapter 187, Digitalis Glycosides).
Some children with congenital heart disease require lifelong
anticoagulant therapy to prevent shunt occlusion or thrombosis of
surgically implanted valves or grafts. The risk of serious bleeding
is small, but must be considered in any elective repair of fractures
or lacerations. Prothrombin time and the international normalized ratio
should be monitored. Reversal of anticoagulation with vitamin
K or fresh frozen plasma should be undertaken only after consultation with
a pediatric cardiologist.
Anemia and Polycythemia
in Cyanotic Congenital Heart Disease
Children with cyanotic congenital heart defects develop an increase
in hemoglobin concentration to compensate for hypoxemia. When hemoglobin concentrations
fall to normal, these infants can become symptomatic, with tachycardia,
feeding difficulty, or CHF. Conversely, polycythemia causes increased
blood viscosity and the potential for cerebrovascular complications.
Iron supplementation is important for the prevention of anemia.
When polycythemia occurs, therapeutic phlebotomy may be warranted.
in Congenital Heart Disease
Although healthy children rarely develop problems with common
viral pathogens such as influenza virus, parainfluenza virus, or
respiratory syncytial virus, children with congenital heart disease
are at high risk for serious complications from infection by these
agents. Recognizing minor early infections with these pathogens
and differentiating them from the symptoms of CHF is a challenge,
even for seasoned clinicians. Children with lesions that increase pulmonary
blood flow are at greater risk because of pooling of alveolar secretions.
Pooled secretions allow for stasis and secondary bacterial overgrowth.
Dramatic increases in mortality and morbidity are evident among
affected infants. No effective therapy is available for parainfluenza
virus infection, but oseltamivir may be useful in influenza, and
annual immunization against seasonal influenza is recommended for
infants with congenital heart defects. Antiviral therapy for respiratory
syncytial virus infection is controversial, but prevention with
virus-specific immune globulin is recommended for most infants with
congenital heart defects.
Children with congenital heart disease are at risk of developing
endocarditis. Uncorrected congenital heart defects carry a 0.1% to
0.2% annual risk of endocarditis, which falls to 0.02% after
correction of most lesions. The highest risk is seen for uncorrected
complex lesions and may be as high as 1.5% per year in
these cases, whereas ASD, VSD, PDA, coarctation, and pulmonary stenosis
carry low risk. Transient iatrogenic bacteremia produced by procedures
such as dental work or respiratory manipulation can lead to localized
colonization and infection. Although the focus of most primary care
providers is toward prevention of this disease, cases still occur.
The usual presentation is unexplained fever in children with known
congenital heart disease. Appropriate evaluation includes multiple
blood cultures, urine culture and analysis, and complete blood count.
Parenteral or oral antibiotics should be administered in consultation
with a pediatric cardiologist familiar with the child’s
history. In cases with a known source of infection, such as otitis
media or pneumonia, multiple blood cultures should be performed,
and appropriate therapy should be directed at the site of primary
infection. Acutely ill children with high fever require hospitalization,
multiple blood cultures, and echocardiographic study of the heart.
Usually, treatment is instituted after culture specimens are obtained
and is directed toward the most common pathogens. Establishment
of a diagnosis is followed by 4 to 6 weeks of IV antibiotic therapy.27 Endocarditis
is discussed further in Chapter 122B, Pediatric Heart Disease: Acquired Heart Disease.
Prophylaxis Prior to Procedures
Prophylactic treatment is recommended for patients who have congenital
heart malformations or who have had rheumatic fever with valvular
disease and who are undergoing surgical or dental procedures or
instrumentation involving mucosal surfaces. The latest prophylaxis
guidelines are reviewed in Chapter 122B, Pediatric Heart Disease: Acquired Heart Disease and may be found at http://www.americanheart.org/presenter.jhtml?identifier=3004539.
Fever in Infants with Heart Disease
Infants and children with known heart disease are prone to the
same illnesses as other children. Although occult bacteremia has
the same probability of occurrence in children with congenital heart
disease as in children without such disease (see Chapter 113, Fever and Serious Bacterial Illness), bacterial endocarditis
is a potential sequel, and parenteral antibiotics (ceftriaxone, 50
milligrams/kg) should be administered presumptively. A
follow-up visit in 12 to 24 hours is mandatory for any child who
is discharged home from the ED.