This study was designed to analyze the cardiac effects of aging and of hypertension in patients with essential hypertension and with or without left ventricular hypertrophy (LVH). Thirty-one patients <55 years old and 66 patients >64 years old with essential hypertension were divided according to the presence or absence of LVH. Cardiac functional structure was assessed by 2D-guided M-mode echocardiography. The peak filling rate and the duration of rapid filling were obtained by digitizing septal and posterior wall echoes. In the older group only was systolic function significantly impaired in subjects with LVH when compared with subjects without LVH [velocity of circumferential fiber shortening (L/msec): 1.40+/-0.24 v 1.18+/-0.25; fractional fiber shortening (%): 43.06+/-5.02 v 36.26+/-7.1; ejection fraction (%): 81.1+/-5.1 v 73.13+/-9.2; P < .05]. Older patients, even without LVH, showed a longer duration of rapid filling (321.0+/-108.3 msec) and lower peak filling rate (7.01+/-1.86 cm/sec) in comparison with younger persons with or without LVH. In the older subjects the increase in left ventricular mass was associated with a decrease of velocity of circumferential fiber shortening (r = -0.48, P < .01), fractional fiber shortening (r = -0.40, P < .01), and ejection fraction = -0.50, P < .01), whereas there was no correlation in the younger group. The present findings of impaired diastolic filling even in the absence of LVH in the elderly, and the deterioration of systolic function parallel to the increase in LV mass suggest that aging is associated with a decrease in the number of functioning contractile elements per unit of cardiac mass.