Quantitative study of ageing changes in the human sinoatrial node and internodal tracts.

Abstract

Quantitative analysis of the amount of muscle,fat, and collagen in the human sinoatrial node and internodal tracts has been carried out. Subjects under 50 were compared with those over 75 years of age at death. In old age there is a significant fall in the amount of muscle present in the sinoatrial node and internodal tracts.