Abstract
Seventy-seven autopsy cases were examined about aging process of conduction tissue (A-V node, His bundle and bundle branch). With advancing age, the following changes occured : 1) Fine reticular fibers extended into A-V node and His-bundle from central fibrous body at first decade. After 30 years age collagenous fibers from central fibrous body connected with perivascular fibrosis and then nodal tissue was completely divided an individual nodal fiber. After 50 years age a portion of bundle branch frequently showed focal loss. 2) Nodal fibrosis was related to the myocardial fibrosis, but nodal fibrosis was milder than that of myocardial fibrosis. Close relation between nodal fibrosis and sclerotic change of nodal artery was not found. 3) Fatty infiltration in the conduction tissue was frequently found in all age groups, especially over 4th decade. It was no tendency of increase with advancing age.
