Pathology of amyloidosis and amyloid heart disease.

Amyloidosis is a family of disorders of the immune system. Each member of the family is characterized clinically by a unique syndrome and chemically by a specific amyloid fibril protein. The diagnosis of amyloidosis requires histopathologic identification of amyloid deposits in the affected tissues. Since none of the commonly used histochemical stains is specific for amyloid and their sensitivity is variable, application of a battery of staining methods (two or more) is essential for the histologic diagnosis of amyloidosis. The heart may be affected in any form of systemic amyloidosis and in senile amyloidosis. Cardiac amyloidosis is an important cause of progressive heart failure and refractory arrhythmia of obscure origin, especially in elderly persons. The average survival time of amyloid heart disease after the onset of symptoms is less than 3 years. Clinically, amyloid heart disease may mimic constrictive pericarditis, coronary artery disease, valvular heart disease, and idiopathic hypertrophic or congestive cardiomyopathy. A confirmatory biopsy is needed for diagnosis since cardiac amyloidosis has no pathognomonic symptoms and signs, nor diagnostic electrocardiographic, radiologic, cardioangiographic and echocardiographic findings.