Figure 1: Heart size, heart weight, body weight and heart weight to body weight ratio were significantly changed with age in F344XBN rats. A- Image series depicting hearts immediately after excision from the rats; B- Heart weight to body weight ratio significantly increased in very aged 33 and 36-month animals compared to 6-, 27- and 30-month animals. Data are mean ± SE (n=6). * indicates significant difference from 6-month control, $ indicates significant difference from 27-month, # indicates significant difference from 30-month animals (P<0.05).