Its principal abnormality is diastolic dysfunction. Differentiation from constrictive pericarditis, a clinically similar entity, is difficult but important since the treatment options and prognosis differ drastically. 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.
Systolic function remains normal or near normal until late stages.
EMF may account for up to one fourth of deaths due to cardiac disease in those areas. 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. Patients often present at an advanced stage of disease with pronounced cardiopulmonary symptoms. However, secondary infiltrative myocardial diseases, which are actually cardiac manifestations of systemic diseases, often are grouped together with cardiomyopathies.