Spectrum of Restrictive and Infiltrative Cardiomyopathies: Part 1 of a 2-Part Series.

Restrictive cardiomyopathies are the least common form of heart muscle disease. They are characterized as infiltrative and noninfiltrative, storage diseases, and endomyocardial disorders. Genetic diseases commonly present during childhood or adolescence. However, a growing percentage of elderly patients with heart failure with preserved ejection fraction are being recognized as having forms of restrictive cardiomyopathy, particularly cardiac amyloidosis. Noninvasive evaluation has replaced endomyocardial biopsy in the diagnostic evaluation of most suspected etiologies. The detection of infiltrative cardiomyopathies, including lysosomal and glycogen storage disorders, iron overload, and amyloidosis (both light chain amyloidosis and transthyretin amyloidosis variants), as well as inflammatory diseases such as sarcoidosis has slowly led to improved outcomes via disease-specific therapies.