Amyloid in the aged heart: frequency and clinical significance.

Cardiac amyloid accumulation is a common autopsy finding in elderly persons, the frequency increasing with each advancing age decade. In most cases the deposits are microscopic, confined to the atrial subendocardium, and of dubious significance. In a few cases, however, there is much more extensive cardiac involvement, with infiltration of the ventricular musculature and intracardiac conduction system. In the authors' recent autopsy study of 100 patients over 60 years of age, 10 had diffuse cardiac amyloidosis with biventricular involvement. Microscopically, the amyloid deposits often resembled foci of interstitial fibrosis. Significant cardiac enlargement (weight greater than 380 gm) was present in only 2 of these patients, and in only one of them were the clinical signs and symptoms clearly attributable attributable to the amyloid infiltration. It was difficult to assess the possible contribution of ventricular amyloid to congestive failure since most of the patients also had coronary arteriosclerosis. In the aged, clinically significant cardiac amyloidosis associated with cardiac enlargement appears to be part of a disease spectrum more commonly characterized by focal, clinically insignificant cardiac amyloid deposits. Yet several features suggest that senile cardiac amyloidosis may differ from the clinically significant cardiac amyloidosis occassionally seen in younger patients.