Abstract
To study the hemodynamic characteristics of elderly hypertensives, elderly subjects (≥65 years old) were divided into normotensives (NT, n=15), borderline hypertensives (BH, n=10) and established hypertensives (EH, n=20) and compared each group with similarly divided middle aged subjects (≥35 years old, <65 years old), NT (n=23), BH (n=112) and EH (n=79). An attempt was also made to clarify what factor is most important regarding left ventricular hypertrophy (LVH) in elderly hypertensives. The results showed that with advancing age, cardiac output and stroke volume decrease (p<0.05), total peripheral resistance and volume-elasticity index increase (p<0.05), daily lability of systolic pressure increases and the baroreceptor slope increases. Furthermore, almost all of these tendencies are exacerbated by hypertension (p<0.05). With advancing age, pressure response to infused noradrenaline is enhanced (p<0.05), but on exercise, there are wide variations in each group and no distinct differences were observed. Echocardiographic examinations revealed LVH in 50% of elderly hypertensives. There were no apparent differences between both groups with or without LVH in their family and personal histories of hypertension, resting hemodynamics, hormonal examinations and hypertensive complications other than the heart. However, on exercise, the pressure response was more enhanced in the group with LVH than in the group without LVH (p<0.05). There was no significant correlation between resting systolic pressure (SBP) and left ventricular mass index (LVMi), but, there was relatively good correlation (r=0.563, p<0.05) between SBP at peak exercise and LVMi. Using delta SBP/delta HR as a parameter of pressure responsibility on exercise test, 9 out of 10 patients with LVH showed above 1.0, while all of 10 patients without LVH showed under 1.0. Pressure response to infused noradrenaline seems to be more enhanced in the group with LVH than in the group without LVH. It was concluded that enhanced pressure responsiveness to recurring stress might induce or at least sustain LVH in hypertensives, due to enhanced alpha-adrenoceptor responsiveness.
