Weisfeldt M
Department of Medicine, Columbia-Presbyterian Medical Center, New York, NY 10032, USA.
Am J Hypertens. 1998 Mar;11(3 Pt 2):41S-45S. doi: 10.1016/s0895-7061(98)00009-0.
I have presented a picture of cardiovascular aging that resembles the situation with vision, where in the absence of actual disease, near vision changes with age and cataracts appear with age but after these are corrected, vision remains markedly unchanged with age. For the undiseased heart, intrinsic cardiac muscle function and the inotropic response to nonsympathetic mediators, along with coronary perfusion, are well maintained with age. There are, however, some changes that do occur with age. Cellular hypertrophy occurs, both because of cell drop out and because of some chamber hypertrophy secondary to increased impedance to left ventricular ejection. As a result of the hypertrophy, there is some prolongation of systole secondary to delayed relaxation. This is typical of what occurs in hypertension induced hypertrophy as well. These age-related changes are of critical importance and are the background for the entire discussion of the interplay between hypertension and disease. The large arteries do in fact stiffen with age. Thus, even without hypertension, there is an age-related increased impedance to ejection, a greater systolic load, a lower coronary perfusion pressure, and an increased pulse wave velocity. Added to this is the failure of the entire beta-sympathetic system to respond as well in the elderly as in the younger individuals with a resultant decrease in the vasodilating response. Both the chronotropic and inotropic response to sympathetic mediation is diminished so that states that put sudden loads on the left ventricle, such as accelerated hypertension or myocardial infarction, have more severe results in the elderly. Also acute hypertension may produce less hypertrophy in the elderly and therefore place more hemodynamic stress on the left ventricle than in young adults.
我已呈现了一幅心血管衰老的图景，它类似于视力方面的情况，即在没有实际疾病的情况下，近视力会随年龄变化，白内障也会随年龄出现，但在这些问题得到矫正后，视力随年龄增长仍显著不变。对于未患病的心脏，心脏固有肌肉功能、对非交感介质的变力反应以及冠状动脉灌注，都会随年龄增长得到良好维持。然而，确实会有一些随年龄出现的变化。细胞肥大的发生，一方面是由于细胞丢失，另一方面是由于左心室射血阻抗增加继发的一些腔室肥大。由于肥大，舒张延迟会导致收缩期有所延长。这在高血压引起的肥大中也很典型。这些与年龄相关的变化至关重要，是整个关于高血压与疾病相互作用讨论的背景。事实上，大动脉会随年龄变硬。因此，即使没有高血压，也会有与年龄相关的射血阻抗增加、更大的收缩期负荷、更低的冠状动脉灌注压以及脉搏波速度增加。此外，整个β - 交感神经系统在老年人中的反应不如年轻人，导致血管舒张反应降低。对交感神经介导的变时和变力反应均减弱，因此，给左心室施加突然负荷的情况，如急进性高血压或心肌梗死，在老年人中会产生更严重的后果。而且，急性高血压在老年人中可能产生的肥大较少，因此比在年轻人中给左心室带来更大的血流动力学压力。
