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一、老年的循环生理心脏最重要的功能是根据身体的需要维持心排出量(CO)。老年人由于身体肌肉量的减少,基础代谢率的下降,CO逐年降低。Brandfonbrener等证明:CO从23.6岁时的6.49升/分(3.72升/分/米~2)降低到82岁时的3.87升/分(2.36升/分/米~2)。这种CO的减少主要是由于每搏输出量(SV)的减少比心率减少更明显。SV从85.6毫升(48.9毫升/米~2)减少到60.1毫升(36.5毫升/米~2)。与SV有关的因素是前负荷、心肌收缩力和后负荷。等容舒张期随年龄增长而延长。由于年龄增长而动脉硬化,增加了阻抗,左室射血阻抗(后负荷)的增加也是SV下降的原因之一。左室舒张末压在安静时是正常范围,运动时上升。运动时的最大氧需要量从20岁以后随年龄增长而减少。形态学的变化:老年性淀粉样变一般只限于心房,少数可在心室看到散在的病变。老年人心脏可发生纤维性支架的特发性硬化改变。另外,老年人没有明
First, the elderly circulatory physiology The most important function of the heart is to maintain cardiac output (CO) according to the needs of the body. Elderly due to the reduction of body muscle mass, basal metabolic rate decreased, CO decreased year by year. Brandfonbrener et al. Demonstrated that CO decreased from 6.49 liters / minute (3.72 liters / minute / meter 2) at 23.6 years to 3.87 liters / minute (2.36 liters / minute / meter 2) at 82 years of age. This decrease in CO is mainly due to a reduction in stroke volume (SV) which is more pronounced than a decrease in heart rate. SV was reduced from 85.6 ml (48.9 ml / m ~ 2) to 60.1 ml (36.5 ml / m ~ 2). Factors related to SV are preload, myocardial contractility and postload. Isovolumic relaxation with age and prolongation. Due to age and atherosclerosis, increased impedance, left ventricular ejection resistance (afterload) increase is also one of the reasons for the decline in SV. Left ventricular end-diastolic pressure in the quiet is the normal range, exercise increased. The maximum oxygen requirement during exercise decreases with age after the age of 20. Morphological changes: senile amyloidosis is generally limited to the atrium, a small number of scattered lesions can be seen in the ventricle. Elderly cardiac fibrosis can occur idiopathic sclerosis changes. In addition, the elderly did not know