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Key Features

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  • Annual incidence is 4–8 cases per 100,000 population in the United States and Europe

  • Although usually idiopathic, identifiable causes of dilated cardiomyopathy include

    • Viral myocarditis

    • Untreated tachyarrhythmias

    • Left heart obstructive lesions

    • Congenital abnormalities of the coronary arteries

    • Medication toxicity (eg, anthracycline)

    • Genetic (eg, dystrophin gene defects, sarcomeric mutations)

    • Metabolic diseases (inborn errors of fatty acid oxidation and mitochondrial oxidative phosphorylation defects)

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Clinical Findings

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  • Presenting symptoms can resemble a viral respiratory infection, pneumonia, or asthma

  • Decreased exercise tolerance

  • Failure to thrive

  • Diaphoresis

  • Tachypnea

  • As the heart continues to deteriorate, congestive signs such as hepatomegaly and rales develop

  • Prominent gallop can be appreciated on examination

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Diagnosis

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  • Chest radiograph shows generalized cardiomegaly with or without pulmonary venous congestion

  • Electrocardiography

    • Sinus tachycardia with ST-T segment changes

    • Criteria for right and left ventricular hypertrophy may be met

    • QT interval may be prolonged

    • Supraventricular arrhythmias may be present; evaluation is critical because this arrhythmia is one of the treatable and reversible causes of dilated cardiomyopathy in children

  • Echocardiography

    • Shows LV and left atrial enlargement with decreased LV-shortening fraction and ejection fraction

    • The calculated end-diastolic and end-systolic dimensions are increased and mitral insufficiency is commonly seen

    • A careful evaluation for evidence of structural abnormalities(especially coronary artery anomalies or left heart obstructive lesions) must be performed, especially in infant patients

  • Cardiac catheterization is useful to evaluate hemodynamic status and coronary artery anatomy

  • Endomyocardial biopsies can aid in diagnosis; specimens may show inflammation consistent with

    • Acute myocarditis

    • Abnormal myocyte architecture

    • Myocardial fibrosis

  • Electron micrographs may reveal evidence of mitochondrial or other metabolic disorders

  • Polymerase chain reaction testing may be performed on biopsied specimens to detect viral genome products in infectious myocarditis

  • Cardiopulmonary stress testing is useful

    • For measuring response to medical therapy

    • As an objective assessment of the cardiac limitations on exercise

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Treatment

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  • Combinations of afterload-reducing agents and diuretics used in outpatient management

  • Aspirin or warfarin may be used to prevent thrombus formation in the dilated and poorly contractile cardiac chambers

  • Antiarrhymthmic therapy is sometimes necessary

  • Therapy of the underlying cause of cardiomyopathy is always indicated unless contraindicated

  • Cardiac transplantation is considered if medical management is unsuccessful

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