This chapter reviews the most common types of acquired heart
disease in children: inflammatory and infectious disorders, and
cardiomyopathies, of which the most important is hypertrophic cardiomyopathy
Myocarditis is an inflammatory disorder of the myocardium affecting children
of all ages and is the leading cause of end-stage cardiomyopathy requiring
transplantation. Viral causes include enteroviruses (coxsackie, echovirus,
and poliovirus), as well as mumps, influenza virus, and varicella
zoster virus. Emerging causes are human immunodeficiency
virus–associated myocarditis and chronic Epstein-Barr myocarditis.
Many bacterial species have been associated with myopericarditis
but not myocarditis alone. Noninfectious causes include conditions
such as Kawasaki disease (see discussion below in Kawasaki
Disease) and lupus erythematosus.
Myocarditis is often preceded by a viral respiratory illness.
Presenting signs and symptoms are often respiratory distress, fever, tachypnea,
tachycardia, generalized malaise, fever, and myalgias. Vomiting,
decreased activity, and poor feeding are present. Arrhythmias may complicate
myocarditis and give rise to symptoms of palpitation or syncope
in older children. Chest pain may be a symptom of concurrent pericarditis.1–3
The physical examination reveals signs of decreased cardiac output
and compensatory response: tachycardia, weak pulses, cool extremities
with delayed capillary refill, skin mottling, or cyanotic skin.
Auscultation of the heart may reveal distant heart sounds, an S3 or
S4 gallop, and a regurgitant murmur. There may be signs
of congestive heart failure.
Diagnostic evaluation includes complete blood count, serum chemistries,
and blood cultures to identify bacterial infection. Inflammatory
markers, such as erythrocyte sedimentation rate and C-reactive protein,
are nonspecific but may be elevated. Respiratory viral cultures
or viral titers may help to identify a specific infectious cause.
Troponin T or I may be elevated.
ECG changes are nonspecific, with sinus tachycardia, low QRS
voltages (<5 mm in limb leads), flattened or inverted T waves
with ST- and T-wave changes, and prolongation of the QT interval.
Left ventricular hypertrophy or strain can be seen. Arrhythmias
include premature ventricular contractions, atrial tachycardias,
junctional tachycardia or, occasionally, heart block, or ventricular
Chest x-ray may reveal cardiomegaly and pulmonary edema, and echocardiography
is useful to define cardiac function. Biopsy is the diagnostic gold
Treatment of myocarditis depends upon the cause. Treatment
of heart failure also depends on the specific cause, and treatment modalities
need to be individualized. Treatment consists of afterload reduction,
preload reduction in the case of true volume overload, or inotropic
support. Diuretics will worsen the condition if cardiac output depends
upon preload.1–3 Children with heart failure
need admission to a tertiary care pediatric facility.
Pericarditis is inflammation of the pericardium and has many
causes. Infectious causes are common and can be bacterial, viral,
fungal, parasitic, or tubercular. Viral etiologies predominate in
the infant. Pericarditis is often associated with myocarditis, with
myocarditis the predominant entity. Staphylococcus aureus, Streptococcus