The usefulness of echocardiography in the diagnosis of amyloid cardiomyopathy

Abstract

Echocardiography is important for raising the pretest probability of amyloid cardiomyopathy before endomyocardial biopsy and ^99mTc-labeled pyrophosphate scintigraphy. Left ventricular (LV) granular sparkling has been reported to be a typical finding in amyloid cardiomyopathy. However, newer echocardiographic image processing techniques may reduce the granular appearance. Thus, the usefulness of granular sparkling as a discriminating factor remains limited. The combination of increased LV thickness and low-voltage electrocardiographic pattern was known to be typical for amyloid cardiomyopathy. However, the rate of low voltage is relatively low in amyloid cardiomyopathy. Thus, a decreased voltage/mass ratio may be useful to diagnose amyloid cardiomyopathy. LV apical sparing pattern, which is a pattern of regional differences in deformation in which the longitudinal strain (LS) in the basal and middle segments of the LV is more severely impaired than that in the apical segment, is also a useful echocardiographic finding for diagnosing amyloid cardiomyopathy. However, we revealed that half of patients with amyloid cardiomyopathy did not have LV apical sparing. Thus, we should recognize the limitations of echocardiographic findings in the diagnosis of amyloid cardiomyopathy. When amyloid cardiomyopathy is suspected, hypertrophic cardiomyopathy, Fabry disease, and mitochondrial cardiomyopathy should be included in the differential diagnosis. Thus, the typical echocardiographic findings of these diseases should be recognized. Although echocardiography is useful for diagnosing and differentiating amyloid cardiomyopathy, there are several limitations. Thus, it is important to perform echocardiography with medical consultation about medical and familial history. Comprehensive assessment with not only echocardiography but also medical consultation, electrocardiography, and laboratory findings enables us to diagnose amyloid cardiomyopathy accurately.