Two-dimensional and Doppler echocardiographic assessment of infiltrative cardiomyopathy.

Infiltrative cardiomyopathies can be divided by disease into infiltrative and storage disorders that show an increase in ventricular wall thickness caused by infiltration of pathologic substances between cells, as with amyloid and sarcoid, or deposition within cells, as with iron, glycogen, and lipid. Two-dimensional and Doppler echocardiography are powerful noninvasive tools in the assessment of the anatomic and functional characteristics of these disorders. With cardiac amyloidosis as the prototype, the constellation of findings of a small or normal left ventricular cavity size; markedly increased thickness of the ventricular walls, associated with a highly abnormal texture; and biatrial enlargement make up its characteristic appearance. However, there is a wide spectrum of abnormalities in this disorder, depending on the stage and duration of heart involvement. Doppler assessment of diastolic function is frequently abnormal in cardiac amyloidosis. Cardiac sarcoidosis usually is evident by a dilated segmental cardiomyopathy with regional wall abnormalities. Similarly, hemochromatosis appears as a dilated cardiomyopathy with normal wall thickness. The echocardiographic appearance of glycogen and glycolipid storage diseases is similar to cardiac amyloidosis, and biochemical analysis may be necessary for differentiation. Thus echocardiography is an important tool in the characterization of infiltrative cardiomyopathies.