Cardiomegaly usually is seen on chest radiographs for all three types of cardiomyopathies. The electrocardiogram (ECG) in dilated cardiomyopathy may have nonspecific ST-T wave changes and left ventricular hypertrophy. ECG evidence of right ventricular hypertrophy is present in 25% of children with cardiomyopathy. The ECG with hypertrophic cardiomyopathy is universally abnormal, but changes are nonspecific. Primary hypertrophic cardiomyopathy is associated with a prolonged QT interval. Children with restrictive cardiomyopathies may show atrial enlargement on the ECG. Echocardiography features vary by type of cardiomyopathy.
Dilated cardiomyopathies result in left atrial and ventricular dilation, a decreased shortening fraction, and globally depressed contractility. Asymmetrical septal hypertrophy and left ventricular outflow tract obstruction are seen in hyper-trophic cardiomyopathies. Massive atrial dilation is seen in restrictive cardiomyopathies. Endomyocardial biopsy specimens, obtained while the patient is hemodynamically stable, identify histologic type and allow tests for mitochondrial or infiltrative diseases.
Supportive therapy, including diuretics, inotropic medications, and afterload reduction, is provided for all three types of cardiomyopathy. If a specific etiology can be identified, treatment is directed at the etiology. Symptomatic therapy with close monitoring and follow-up is crucial. Because of the high mortality rate associated with all forms of cardiomyopathy, cardiac transplantation must be considered.
Pericarditis is inflammation of the parietal and visceral surfaces of the pericardium. It is most often viral in origin, with many viruses identified as causative agents. A bacterial etiology is rare but causes a much more serious and symptomatic pericarditis. Staphylococcus aureus and Streptococcus pneumoniae are the most likely bacterial causes. Pericarditis is associated with collagen vascular diseases, such as rheumatoid arthritis, and is seen with uremia (Table 148-1). Postpericardiotomy syndrome is a relatively common form of pericarditis that follows heart surgery.
Pneumococcus, meningococcus*
Coxsackievirus (group A, B) Echovirus Mumps Influenza Epstein-Barr Cytomegalovirus
From Sigman G: Chest pain. In Kliegman RM, Nieder ML, Super DM. editors: Practical Strategies in Pediatric Diagnosis and Therapy, Philadelphia, 1996, WB Saunders.
*Infectious or immune complex.
†Common (viral pericarditis or myopericarditis is probably the most common cause of acute pericarditis in a previously normal host).
Chest pain (worsened if lying down or with inspiration) Dyspnea Malaise Patient assumes sitting position
Fever Tachycardia Friction rub (accentuated by inspiration, body position) Enlarged heart by percussion and x-ray examination Distant heart sounds
As above, plus:
Distended neck veins Hepatomegaly Pulsus paradoxus (>10 mm Hg with inspiration) Narrow pulse pressure Weak pulse, poor peripheral perfusion
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The symptoms of pericarditis (Table 148-2) depend on the amount of fluid in the pericardial space and how fast it accumulates. A small effusion usually is well tolerated. A large effusion may be well tolerated if it accumulates slowly. The faster the fluid accumulates, the sooner the patient is hemodynamically compromised and develops symptoms.