Excerpt from Cardiomyopathy, Restrictive

Synonyms, Key Words, and Related Terms: diastolic dysfunction, restrictive cardiomyopathy, endomyocardial fibrosis, EMF, dip and plateau configuration, dip and plateau pattern, square root pattern, square root configuration, heart failure, cardiac cirrhosis, thromboembolism, low-output cardiac failure

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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.