INTRODUCTION	Section 2 of 10
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Background: Restrictive cardiomyopathy is the least common of the 3 clinically recognized and described cardiomyopathies. Its principal abnormality is diastolic dysfunction. Differentiation from constrictive pericarditis, a clinically similar entity, is difficult but important because the treatment options and prognosis differ drastically.

Pathophysiology: Restrictive cardiomyopathy can be idiopathic or secondary to a heart muscle disease that manifests as restrictive physiology. The common hemodynamic disturbance is impairment of ventricular filling due to the thickening and increased rigidity of the endocardium and myocardium secondary to infiltration by amyloid tissue or by fibrosis. Ventricular diastolic pressures are elevated and may inscribe a "dip and plateau" or "square root" pattern. Systolic function remains normal or near normal until late stages.

Frequency:

• In the US: Occurrence of restrictive cardiomyopathy is rare with no quantifiable incidence.

• Internationally: Endomyocardial fibrosis (EMF), an etiologic factor of idiopathic restrictive cardiomyopathy, is a progressive disease of unknown cause that occurs most commonly in children and young adults in tropical and subtropical Africa, primarily in Uganda and Nigeria. EMF may account for up to one fourth of deaths due to cardiac disease in those areas.

Mortality/Morbidity: The natural history of restrictive cardiomyopathy is especially poor in children with heart failure. Adults experience a prolonged course of heart failure and may have complications of cardiac cirrhosis and thromboembolism. Patients who are refractory to supportive therapy usually die of low-output cardiac failure unless cardiac transplantation is an option.

Race: Natives of Africa, South America, and India are predisposed to EMF.

Age: EMF is most common in children and young adults.

	CLINICAL	Section 3 of 10
Author Information Introduction Clinical Differentials Workup Treatment Medication Follow-up Miscellaneous Bibliography

History:

• Patients often present at an advanced stage of disease with pronounced cardiopulmonary symptoms. The patient's history may reveal the following:

• Angina

• Dyspnea, orthopnea, or dyspnea on exertion

• Paroxysmal nocturnal dyspnea

• Peripheral edema

• Abdominal discomfort, liver tenderness

• Increased abdominal girth, ascites

Physical:

• In addition to the findings listed below, a careful general physical examination must be conducted to search for extracardiac manifestations of a systemic disorder that may cause secondary restrictive cardiomyopathy (eg, hemochromatosis, amyloidosis, sarcoidosis, scleroderma).

• Elevated jugular venous pulse, Kussmaul sign

• y descent blunted relative to x

• S3 and/or S4

• Occasional mitral or tricuspid regurgitation murmur

• Distant heart sounds

• Pulmonary rales

• Peripheral edema

• Pulsus paradoxus - As the restrictive process progresses, no change in blood pressure occurs with inspiration.

Causes:

• According to guidelines of the World Health Organization, cardiomyopathy refers to the disease of the myocardium secondary to an idiopathic cause (ie, primary cardiomyopathies). However, secondary infiltrative myocardial diseases, which are actually cardiac manifestations of systemic diseases, often are grouped together with cardiomyopathies.

• Idiopathic restrictive cardiomyopathy

• EMF

• Loeffler eosinophilic endomyocardial disease

• Secondary restrictive cardiomyopathy

• Hemochromatosis

• Amyloidosis

• Sarcoidosis

• Progressive systemic sclerosis (scleroderma)

• Carcinoid heart disease

• Glycogen storage disease of the heart

• Radiation

• Metastatic malignancy

• Anthracycline toxicity