CHF is a clinical syndrome in which the heart is unable to pump enough blood to the body to meet its needs, to dispose of systemic or pulmonary venous return adequately, or a combination of the two.
A. Causes
The heart failure syndrome may arise from diverse causes. By far the most common causes of CHF in infancy are CHDs. Beyond infancy, myocardial dysfunction of various etiologies is an important cause of CHF. Tachyarrhythmias and heart block can also cause heart failure at any age.
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Congenital heart disease
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Volume overload lesions such as VSD, PDA, and ECD are the most common causes of CHF in the first 6 months of life.
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In infancy, the time of the onset of CHF varies predictably with the type of defect. Table 19.1 lists common defects according to the age at which CHF develops.
Table 19.1
Causes of Congestive Heart Failure Resulting From Congenital Heart Disease
AS , aortic stenosis; COA , coarctation of the aorta; ECD , endocardial cushion defect; HLHS , hypoplastic left heart syndrome; PA , pulmonary artery; PDA , patent ductus arteriosus; PS , pulmonary stenosis; TAPVR , total anomalous pulmonary venous return; TGA , transposition of the great arteries; VSD , ventricular septal defect.
Age Of Onset
Cause
At birth
HLHS
Volume overload lesions
Severe tricuspid or pulmonary insufficiency
Large systemic arteriovenous fistula
First wk
TGA
PDA in small premature infants
HLHS (with more favorable anatomy)
TAPVR with pulmonary venous obstruction
Critical AS or PS
Systemic arteriovenous fistula
1-4 wk
COA with associated anomalies
Critical AS
Large left-to-right shunt lesions (VSD, PDA) in premature infants
All other lesions previously listed
4-6 wk
Some left-to-right shunt lesions such as ECD
6 wk-4 mo
Large VSD
Large PDA
Others such as anomalous left coronary artery from the PA
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Large L-R shunt lesions, such as VSD and PDA, do not cause CHF before 6 to 8 weeks of age because the PVR does not fall low enough to cause a large shunt until this age. CHF may occur earlier in premature infants (within the first month) because of an earlier fall in the PVR.
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Note that children with TOF do not develop CHF and that ASDs rarely cause CHF in the pediatric age group, although they can cause CHF in adulthood.
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Acquired heart disease. Acquired heart disease of various etiologies can lead to CHF. Common entities (with the approximate time of onset of CHF) are as follows.
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Viral myocarditis (in toddlers, occasionally in neonates with fulminating course).
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Myocarditis associated with Kawasaki disease (1 to 4 years of age).
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Acute rheumatic carditis (in school-age children).
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Rheumatic valvular heart diseases, such as MR or AR (older children and adults).
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Dilated cardiomyopathy (at any age during childhood and adolescence).
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Doxorubicin cardiomyopathy (months to years after chemotherapy).
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Cardiomyopathies associated with muscular dystrophy and Friedreich ataxia (in older children and adolescents).
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Miscellaneous causes
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Metabolic abnormalities (severe hypoxia, acidosis, hypoglycemia, hypocalcemia) (in newborns)
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Hyperthyroidism (at any age)
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SVT (in early infancy)
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Complete heart block associated with CHDs (in the newborn period or early infancy)
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Severe anemia (at any age), hydrops fetalis (neonates), and sicklemia (childhood and adolescence)
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Bronchopulmonary dysplasia (BPD) with right-sided failure (the first few months of life)
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Primary carnitine deficiency (2 to 4 years)
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Acute cor pulmonary caused by acute airway obstruction (during early childhood)
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Acute systemic hypertension with glomerulonephritis (school-age children)
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B. Diagnosis of CHF
The diagnosis of CHF relies on several sources of clinical findings, including history, physical examination, chest radiographs, and echo studies. There is no single laboratory test that is diagnostic of CHF in pediatric patients.
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Poor feeding of recent onset, tachypnea, poor weight gain, and cold sweat on the forehead suggest CHF in infants. In older children, shortness of breath, especially with activities, easy fatigability, puffy eyelids, or swollen feet, may be presenting complaints.
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Physical findings can be divided by pathophysiologic subgroups.
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Compensatory responses to impaired cardiac function.
- (1)
Tachycardia, gallop rhythm, weak and thready pulse, and cardiomegaly on chest radiographs.
- (2)
Signs of increased sympathetic discharges (growth failure, perspiration, and cold wet skin).
- (1)
- b.
Signs of pulmonary venous congestion (left-sided failure) include tachypnea, dyspnea on exertion (or poor feeding in small infants), orthopnea in older children, and rarely wheezing and pulmonary crackles.
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Signs of systemic venous congestion (right-sided failure) include hepatomegaly and puffy eyelids. Distended neck veins and ankle edema are not seen in infants.
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Cardiomegaly on chest radiograph is almost always present, except when the pulmonary venous return is obstructed; in that case pulmonary edema or venous congestion will be present.
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The electrocardiogram (ECG) is not helpful in deciding whether the patient is in CHF, although it may be helpful in determining the cause.
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Echo studies confirm the presence of chamber enlargement or impaired LV function and help determine the cause of CHF.
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Increased levels of plasma natriuretic peptides (atrial natriuretic peptide [ANP] and B-type natriuretic peptide [BNP]) are helpful in differentiating causes of dyspnea (lungs vs. heart) in adult patients, but the usefulness of the levels of these peptides is limited in pediatric use. Plasma levels of these peptides are normally elevated in the first weeks of life.
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Endomyocardial biopsy obtained during cardiac catheterization offers a new approach to specific diagnosis of the cause of CHF, such as inflammatory disease, infectious process, or metabolic disorder.
C. Management
The treatment of CHF consists of (1) elimination of the underlying causes or correction of precipitating or contributing causes (e.g., infection, anemia, arrhythmias, fever, hypertension), (2) general supportive measures, and (3) control of heart failure state by use of drugs, such as inotropic agents, diuretics, and afterload-reducing agents.
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Treatment of underlying causes or contributing factors.
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Treatment or surgery of underlying CHDs or valvular heart disease when feasible (the best approach for complete cure).
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Antihypertensive treatment for hypertension.
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Antiarrhythmic agents or cardiac pacemaker therapy for arrhythmias or heart block.
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Treatment of hyperthyroidism if it is the cause of CHF.
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Antipyretics for fever.
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Antibiotics for a concomitant infection.
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Packed cell transfusion for anemia (to raise the hematocrit to ≥35%).
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General measures.
- a.
Nutritional supports are important. Infants in CHF need significantly higher caloric intakes than recommended for average children. The required calorie intakes may be as high as 150 to 160 kcal/kg/day for infants in CHF.
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Increasing caloric density of feeding may be required and it may be accomplished with fortification of feeding ( Box 19.1 ). Frequent small feedings are better tolerated than large feedings in infants.
Box 19.1
Increasing Caloric Density of Feedings.
From Wright, G. E., & Rochini, A. P. (2002). Primary and general care of the child with congenital heart disease, ACC Current Journal Review, 11 (2), 89-93.
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Human milk fortifier (Enfamil, Mead Johnson), 1 packet per 25 ml of breast milk = 24 kcal/oz
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Formula concentration to 24 kcal/oz by:
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1 cup powdered formula + 3 cups water or
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4 oz ready-to-feed + {1/2} scoop powdered formula
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Supplementation of formula to 26-30 kcal/oz is accomplished in the following manner.
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Fat modular products
- b.
Medium chain triglycerides (MCT) oil (Mead Johnson), 8 kcal/mL
- c.
Microlipid (safflower oil emulsion, Mead Johnson), 4.5 kcal/mL
- d.
Low-osmolality polymers
- e.
Polycose (Ross), 23 kcal/tablespoon
- f.
Moducal (Mead Johnson), 30 kcal/tablespoon
- a.
- 4.
Pediasure (Ross), 30 kcal/oz ready-to-feed (for children older than 1 year)
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