REGULATION OF LEFT VENTRICULAR VOLUMES AT REST AND DURING STRESS

静息时和应激时左心室容积的调节

• 批准号: 3789784
• 负责人: E LAKATTA
• 金额: --
• 依托单位: NATIONAL INSTITUTE ON AGING
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3789784
• 关键词: aerobic exercise; aging; beta adrenergic agent; beta antiadrenergic agent; heart circulation; heart contraction; heart imaging /visualization /scanning; heart pharmacology; heart ventricle; human middle age (35-64); human old age (65+); intracardiac volume; male; propranolol; young adult human (21-34)

Radionuclide ventriculography can accurately track changes in left ventricular (LV) volumes at rest and during vigorous aerobic exercise (EX). Although age-associated changes in LV volumes and ejection fraction (EF) have been shown during EX in prior studies, the role of age changes in cardiovascular fitness on these LV parameters during EX has not been assessed. To determine the effect of age on EX LV volumes, independent of physical fitness level, we obtained gated cardiac blood pool scans during graded maximal upright cycle EX in 95 healthy men ages 23-86 yr. At maximal effort in the overall group, LV end-diastolic volume index (EDVI) and end-systolic volume index (ESVI) increased with age (r = 0.37, p<.01 and r = 0.46, p<.001 re-spectively) while LVEF declined with age, r = - 0.46, p<.001 and stroke volume index (SVI) was unrelated to age. In a subset of 49 men of homogeneous fitness (maximal workload 125-150 watts), EDVI and ESVI increased and LVEF decreased with age as in the overall sample, but SVI increased with age (r = 0.39, p<.01) due to an accent- uated increase in EDVI (r = 0.51, p<.001). Age differences in the cardiac response to beta-adrenergic stimulation may underlie aging changes in cardiovascular EX hemodynamics. One way to test this hypothesis is to administer a beta-adrenergic blocking drug to normal individuals across a broad age range and compare the EX re-sponse to that in the unblocked condition The response to strenuous aerobic EX is mediated in large part by beta-adrenergic activation, the efficiency of which de-clines with advancing age. To ascertain whether acute beta-blockade would attenu-ate these normative age changes in cardiovascular EX performance, we performed maximal cycle EX in a group of BLSA men after intravenous propranolol. In 25 men ages 28-72 yr given intravenous propranolol, EDVI at peak workload declined with age (r= -0.20) causing an age-associated decline in SVI (r= 0.48, p<0.05) not pre-sent in the unblocked men. The decline in heart with age in propranolol-treated men was blunted (0.46 beats/min/yr) compared to controls (1.09 beats/min/yr). Max-imal LVEF declined with age similarly in the presence (r= -0.50, p<.01) and the absence (r= -0.45, p<.0001) of beta-adrenergic blockade. The primary reason for the slope shifts in the age regressions in the presence of propranolol was a large increase in EDVI and SVI and a large decrease in HR in younger men. Thus, while the age-associated decline in maximal LVEF is unaffected, acute beta-blockade reverses the age-associated ventricular dilatation during upright cycle and blunts the de-cline in maximal HR. The net effect is an accentuated decline of maximal CI with age.

放射性核素心室造影可准确追踪左心室变化 静息时和剧烈有氧运动时的心室 (LV) 容积 （前任）。尽管左心室容量和射血分数与年龄相关 (EF) 在之前的研究中已经表明，年龄变化的作用 EX 期间这些 LV 参数的心血管健康尚未得到证实 评估。确定年龄对 EX LV 体积的影响，独立于 身体健康水平，我们在期间进行了门控心脏血池扫描 对 95 名年龄在 23-86 岁的健康男性进行最大直立循环 EX 分级。在 整个组中的最大努力，左心室舒张末期容积指数 (EDVI) 收缩末期容积指数 (ESVI) 随着年龄的增长而增加 (r = 0.37, p<.01 r = 0.46，p<.001）而 LVEF 随着年龄的增长而下降，r = - 0.46，p<.001，每搏输出量指数 (SVI) 与年龄无关。在一个 49 名身体素质相同的男性子集（最大工作负荷 125-150 瓦）， 与总体情况一样，EDVI 和 ESVI 随年龄增加而 LVEF 降低 样本，但由于口音，SVI 随着年龄的增长而增加 (r = 0.39, p<.01) EDVI 显着增加（r = 0.51，p<.001）。心脏的年龄差异 对β-肾上腺素能刺激的反应可能是衰老变化的基础 心血管 EX 血流动力学。检验这一假设的一种方法是 给正常人服用β-肾上腺素能阻滞药物 广泛的年龄范围，并将 EX 反应与未受阻的情况进行比较 对剧烈有氧 EX 的反应在很大程度上是介导的 通过β-肾上腺素能激活，其效率随 年龄的增长。确定急性β-阻断是否会减弱 这些心血管 EX 表现的正常年龄变化，我们进行了 一组 BLSA 男性静脉注射普萘洛尔后的最大周期 EX。在 25 名 28-72 岁的男性在高峰工作量时静脉注射普萘洛尔、EDVI 随着年龄的增长而下降 (r= -0.20)，导致 SVI 与年龄相关的下降 (r= 0.48，p<0.05）在未阻断的男性中不存在。内心的衰退与 与接受普萘洛尔治疗的男性相比，接受普萘洛尔治疗的男性的年龄变短（0.46 次/分钟/年） 控制（1.09 次/分钟/年）。最大 LVEF 随着年龄的增长而下降， 存在（r= -0.50，p<.01）和不存在（r= -0.45，p<.0001） β-肾上腺素能阻断剂。造成坡度变化的主要原因 普萘洛尔存在下的年龄倒退显着增加 年轻男性的 EDVI 和 SVI 以及心率大幅下降。因此，虽然 与年龄相关的最大 LVEF 下降不受影响，急性 β 受体阻滞剂 逆转直立循环期间与年龄相关的心室扩张 并减缓最大心率的下降。净效应是突出的 最大 CI 随着年龄的增长而下降。