Pediatric Restrictive Cardiomyopathy Workup

Updated: May 01, 2017
  • Author: Kimberly Y Lin, MD; Chief Editor: Syamasundar Rao Patnana, MD  more...
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Workup

Approach Considerations

Laboratory studies generally do not contribute to the diagnosis of restrictive cardiomyopathy (RCM). Echocardiography is often diagnostic and is very useful in distinguishing RCM from constrictive pericarditis (CP); cardiac computed tomography (CT) or magnetic resonance imaging (MRI) may also be a helpful adjunct in this respect. Cardiac catheterization is generally indicated to assess hemodynamics. Electrocardiography (ECG) usually reveals abnormalities. Endomyocardial biopsy may reveal a specific cause but appears to be much more helpful in adults than in children.

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Echocardiography

Echocardiography is often diagnostic of RCM. Results usually include marked atrial enlargement with normal left ventricular end-diastolic dimensions (see the image below). Ventricular hypertrophy and atrioventricular valve dysfunction may also be present. Atrial thrombi and pulmonary vein atrial flow reversal duration that exceeds mitral a wave duration have also been described.

Echocardiographic 4-chamber view of a child with r Echocardiographic 4-chamber view of a child with restrictive cardiomyopathy demonstrating characteristic marked enlargement of right atrium (RA) and left atrium (LA), which are larger than left ventricle (LV).

Echocardiography can be very useful in distinguishing RCM from CP. [31, 32] For example, echocardiographic evidence of minimal respiratory variation in Doppler ventricular inflow signals is observed in patients with RCM; in comparison, significant respiratory variation is observed in patients with CP. [33] Prolongation of the systole-to-diastole ratio is observed in pediatric RCM, although this abnormality is also found in children with dilated cardiomyopathy. Mid-diastolic reversal of flow across mitral and tricuspid valves is also more common in RCM.

Unfortunately, Doppler echocardiographic findings still show overlap between RCM and CP. Echocardiography may reveal a thickened pericardium in patients with CP.

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Electrocardiography

ECG usually reveals evidence of atrial enlargement and ST-T wave changes. Infiltrative diseases can have low voltage changes. An arrhythmia (eg, atrial fibrillation) may be present. Familial RCM can be associated with atrioventricular block.

Because of risk of sudden deterioration and death, some investigators recommend serial ECG and Holter monitoring to observe for evidence of ischemia and arrhythmia. [34]

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Cardiac Catheterization

Pulmonary artery pressures are usually elevated. Right and left ventricular end-diastolic pressures are elevated, and the 2 ventricular end-diastolic pressures are generally discordant, with left ventricular end-diastolic pressure usually being significantly higher (>5 mm Hg) than right ventricular end-diastolic pressure.

The systolic area index, which uses the ratio of right-to-left ventricular systolic pressure-time area during inspiration and expiration as measured during cardiac catheterization, has also been proposed as a means of differentiating between RCM and CP. [35]

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Other Studies

On chest radiography, heart size is usually increased, often with evidence of right or left atrial enlargement. Pulmonary venous congestion is often evident.

Computed tomography (CT) and magnetic resonance imaging (MRI) may be useful for assessing pericardial thickness in patients for whom CP is in the differential diagnosis.

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Tissue Analysis and Histologic Findings

Endomyocardial biopsy may reveal a specific cause but appears to be much more helpful in adults than in children. Thus, indications must be individualized and balanced with the risks of the procedure. [36] Guidelines for the role of endomyocardial biopsy in the management of cardiovascular disease have been proposed. [37]

Findings from biopsy or autopsy are usually abnormal but are not necessarily diagnostic. Varying degrees of myocyte hypertrophy, interstitial fibrosis, myocytolysis, and endocardial sclerosis have been found. In those patients (usually adults) with an infiltrative cause, such as amyloidosis, biopsy findings may be diagnostic.

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