The aging of the heart: weight and structural changes in the left ventricle with age]

Structural alterations of the cardiovascular system with aging are difficult to differentiate from superimposed pathologic processes. To determine whether aging "per se" affects the dimension of the heart, the weight of the heart, and the left ventricle and their rations to body weight, left ventricle wall thickness, the number of myocyte nuclei in the ventricle and the myocyte cell volume per nucleus were measured in 67 autopsies of subjects, 45 males and 22 females, who died from causes independent of cardiovascular diseases, from 17 to 90 years old. With aging, total heart weight increased slightly, while left ventricular and interventricular septum weights after dissection of the subepicardial fat decreased significantly (r = 0.44; p less than 0.001). Although left ventricular wall thickness remained constant with time, left ventricular weight to body weight ratio decreased progressively. At the structural level the number of myocyte nuclei within the left ventricle decreased (r = 0.45; p less than 0.001), whereas myocyte cell volume per nucleus increased (r = 0.30; p greater than 0.05) with age. Thus, the aging process of the heart is associated with a reduction in volume of the myocardial mass resulting from myocyte cell loss and reactive hypertrophy of the spared myocytes.