Senile cardiac amyloidosis: evidence of two different amyloid substances in the ageing heart.

In a material of seventy-two persons over 70 years of age, forty-seven cases of amyloidosis of the heart were found. In thirty-nine cases, deposits occurred only in the atria (isolated artrial amyloidosis, IAA), while in eight cases amyloid also was seen in the ventricles (senile cardiac amyloidosis, SCA). In some of the latter cases, small amyloid deposits occurred in other organs, especially the lungs. Some definite differences existed between the amyloid substance in SCA and IAA. Thus, tryptophan was demonstrated histochemically in SCA but not in IAA, and, furthermore, amyloid fibrils isolated from patients with IAA lacked protein Asca, the fibril subunit protein of senile cardiac amyloid. It is concluded that the ageing heart may be the target of two different forms of amyloid, one only affecting the atria, while the other is more widespread within the heart and sometimes also is found in other organs.