Morphometry of the aging heart.

Myocardial structure was studied in seven geriatric patients (cases), aged 79 to 91, and ten younger adult patients (controls), aged 22 to 52. Myocardial sections of posterior left ventricle (PLV), anterior left ventricle (ALV), and ventricular septum (VS) were studied using computerized morphometry. Each section of heart (PLV, ALV, or VS region) was divided into three zones: subepicardial (epi), midmyocardial (myo), and subendocardial (endo). Interstitial collagen content and nuclear and cell diameters of myocytes were obtained. Large scars were excluded. Student's t-test was used to evaluate differences, which were considered significant at a level of P less than 0.001. No significant zonal or regional variation in collagen content was found in control hearts, where interstitial trichrome-positive tissue comprised 6.61% of the myocardium. By contrast, elderly hearts showed a distinct increase in interstitium in the PLV region (18.3%), as compared with ALV and VS, and as compared with control hearts (P less than 0.001). Relative myocyte hypertrophy with aging was most prominent in a zonal midmyocardial distribution (P less than 0.001). Myocyte nuclei showed shrinking with age in the subepicardial zone (P less than 0.001). These findings indicate there are specific age-related alterations in myocardium, which may relate to functional abnormalities seen in the elderly.