Colan S D, Borow K M, Neumann A
J Am Coll Cardiol. 1984 Oct;4(4):715-24. doi: 10.1016/s0735-1097(84)80397-6.
The velocity of circumferential fiber shortening (Vcf) is an index of myocardial performance which, although sensitive to contractile state, has limited usefulness because of its dependence on left ventricular loading conditions. This study investigated the degree and velocity of left ventricular fiber shortening as it relates to wall stress in an attempt to develop an index of contractility that is independent of preload and heart rate while incorporating afterload. Studies were performed in 78 normal subjects using M-mode echocardiography, phonocardiography and indirect carotid pulse tracings under baseline conditions. In addition, studies were performed on 25 subjects during afterload augmentation with methoxamine, 8 subjects before and during afterload challenge after increased preload with dextran and 7 subjects with enhanced left ventricular contractility with dobutamine. The relation of end-systolic stress to the velocity of fiber shortening and to the rate-corrected velocity of shortening (corrected by normalization to an RR interval of 1) was inversely linear with correlation coefficients of -0.72 and -0.84, respectively. Alterations in afterload, preload or a combination of the two did not significantly affect the end-systolic wall stress/rate-corrected velocity of shortening relation, whereas during inotropic stimulation, the values were higher, with 94% of the data points above the normal range. Age did not appear to affect the range of normal values for this index. In contrast, the end-systolic wall stress/fractional shortening relation was not independent of preload status, responding in a manner similar to that seen with a positive inotropic intervention. Thus, the velocity of circumferential fiber shortening normalized for heart rate is inversely related to end-systolic wall stress in a linear fashion. Accurate quantitation can be performed by noninvasive means and a range of normal values determined. This index is a sensitive measure of contractile state that is independent of preload, normalized for heart rate and incorporates afterload. In contrast, the end-systolic wall stress/fractional shortening relation is dependent on end-diastolic fiber length in the range of physiologically relevant changes in preload.
圆周纤维缩短速度（Vcf）是心肌功能的一个指标，尽管它对收缩状态敏感，但由于其依赖于左心室负荷条件，其用途有限。本研究调查了左心室纤维缩短的程度和速度及其与壁应力的关系，试图建立一个独立于前负荷和心率并纳入后负荷的收缩性指标。在78名正常受试者中，在基线条件下使用M型超声心动图、心音图和间接颈动脉脉搏描记进行研究。此外，对25名使用甲氧明增加后负荷的受试者、8名在右旋糖酐增加前负荷后进行后负荷挑战之前和期间的受试者以及7名使用多巴酚丁胺增强左心室收缩性的受试者进行了研究。收缩末期应力与纤维缩短速度以及与速率校正的缩短速度（通过归一化到RR间期为1进行校正）的关系呈反线性，相关系数分别为-0.72和-0.84。后负荷、前负荷或两者的组合改变并未显著影响收缩末期壁应力/速率校正的缩短速度关系，而在变力刺激期间，这些值更高，94%的数据点高于正常范围。年龄似乎并未影响该指标的正常范围。相比之下，收缩末期壁应力/缩短分数关系并不独立于前负荷状态，其反应方式类似于正性变力干预所见。因此，经心率归一化的圆周纤维缩短速度与收缩末期壁应力呈线性反比关系。可以通过非侵入性方法进行准确量化并确定正常范围。该指标是收缩状态的敏感测量指标，独立于前负荷，经心率归一化并纳入后负荷。相比之下，在生理相关的前负荷变化范围内，收缩末期壁应力/缩短分数关系依赖于舒张末期纤维长度。
