The significance of the interrelationship between the intensity of the contractile state and the velocity of relaxation in adapting cardiac muscle to function at high work loads.

The relationship between the amplitude of contraction and the velocity of relaxation has been studied, using papillary muscles isolated from rats and from guinea-pigs. Under isotonic conditions and with varying preloads an increase in the amplitude of contraction is followed by a proportionate increase in the velocity of relaxation. This same relationship was observed in experiments performed under isotonic conditions with different afterloads, provided that the contractile force did not exceed 60% of the maximal isometric value. This correlation disappeared at high work loads under isometric conditions, when the resting length exceeded a critical value. A positive correlation between developed ventricular pressures and the velocity of relaxation was also found in anaesthetized dogs and rats, when the developed pressure increased in response to an increased resistance in the outflow tract.When the frequency at which isolated guinea-pig papillary muscles was stimulated to contract was increased, the velocity of relaxation increased, the increase being proportional to the product of the amplitude and frequency of contraction. This relationship may reflect the existence of an autoregulatory mechanism that preserves the diastolic pause. The cellular basis of this autoregulatory mechanism is probably associated with the overloading of the heart with Ca²⁺; it is impaired by conditions which result in hypertrophy, hypothermia or a raised myoplasmic Ca²⁺.     

组织速度成像评价正常人心动周期时间间期的研究

目的根据组织速度图中速度-时间曲线确定心脏心动周期的时间间期及其正常参考值。方法获取29例健康志愿者标准心尖二腔、心尖长轴和心尖四腔观组织速度图,根据心肌各节段的速度曲线,测量左、右心室各室壁基底段和中段收缩期与舒张期的时间间期。结果组织速度图在各室壁的基底段进行采样和分析,其成功率为100%。对左室室间隔基底段与右室游离壁基底段各时间间期进行配对t检验,显示两者在等容收缩时间、加速收缩时间、收缩达峰时间、等容舒张时间、R波至快速充盈峰值时间、快速充盈时间、心房收缩时间、舒张后期时间、快速充盈加速时间、心房加速时间和舒张早期达峰时间差异均存在显著或极显著性意义(P<0.05或<0.001)。对左室不同室壁的基底段与室间隔基底段的收缩期或舒张期时间间期进行配对t检验分析显示:各收缩时间间期差异均无显著性意义,而左室侧壁与室间隔基底段在快速充盈时间、等容舒张时间、舒张后期时间和R波至心房收缩峰值时间差异均存在极显著性意义。结论组织速度图不仅可以更为精确、直观、定量评价正常人心脏心动周期的时间间期,而且可以定量测量等容收缩时间、等容舒张时间、收缩加速时间和减速时间、舒张加速时间和舒张加速时间等,是一种比心电图更为全面和准确,而且可以快速、实时评价心脏时间间期的可靠方法。     

中西医联合治疗糖尿病周围神经病变效果观察

目的研究中西医联合治疗糖尿病周围神经病变患者的临床效果。方法按照随机数字表法将2017年7月-2018年6月期间本院收治的72例糖尿病周围神经病变患者分为两组,对照组36例采用常规西医治疗,观察组36例采用中西医联合治疗。将两组的神经传导速度、临床疗效、用药安全性进行比对。结果观察组糖尿病周围神经病变患者治疗后正中神经、尺神经的MNCV、SNCV均快于对照组,临床总有效率高于对照组,P<0.05;两组的不良反应发生率进行比较差异无统计学意义,P>0.05。结论中西医联合治疗糖尿病周围神经病变患者具有较高的有效性和安全性。     

脉搏波传导速度在高血压靶器官损害中的临床应用进展

高血压是导致全球心血管疾病发生的最大危险因素,其主要通过靶器官损害危害人类健康。高血压导致心、脑、肾等靶器官损害及其终末期并发症的共同病理学基础是其供应血管发生了动脉僵硬、动脉粥样硬化、狭窄和闭塞。脉搏波传导速度是评估动脉硬度的重要参数之一,也是亚临床靶器官损害的检测指标之一。本综述旨在探讨脉搏波传导速度在高血压靶器官损害中的临床应用价值。