Frank M J, Levinson G E
J Clin Invest. 1968 Jul;47(7):1615-26. doi: 10.1172/JCI105853.
There is a profound need, on both clinical and physiologic grounds, for a measure of the contractile state of the intact ventricle. Such a measure can be obtained by evaluating the force-velocity relationship with a correction for myocardial fiber length. The force-velocity relation can be expressed as the ratio of maximum rate of pressure rise to maximum isovolumetric pressure, a quantity which was described by Hill as the maximum rate of proportional rise of pressure and which is similar to the velocity constant of a chemical reaction. Division of this ratio by an estimate of ventricular circumference corrects for variations due to differences in initial fiber length. This index was evaluated in 11 normal subjects and 46 patients with cardiac disease during left heart catheterization. Maximum rate of pressure rise was obtained by electronic differentiation of the ventricular pressure pulse, and ventricular circumference, assuming a spherical ventricle, was calculated from volumes measured by indicator washout. The contractility index of normal subjects did not differ from that of patients with mitral stenosis, atrial septal defect, or chronic pulmonary disease (patients without left ventricular overloading). In contrast, in patients with left ventricular failure, the indices were more than two standard deviations below the mean value for normal subjects. Such a reduction was not noted in patients with pressure or volume overloading of the left ventricle before the onset of myocardial failure. During exercise, the index rose uniformly in patients without left ventricular disease, responded variably in compensated patients with volume or pressure overloading, and was virtually unchanged in patients with left ventricular decompensation. The administration of isoproterenol or digitalis resulted in increased contractility regardless of the patient's status. It is concluded that the use of this index in physiologic studies of the ventricle and in diagnostic and therapeutic decisions is justified.
基于临床和生理学原因，对于完整心室收缩状态的测量存在着迫切需求。通过评估力-速度关系并对心肌纤维长度进行校正，可获得这样一种测量方法。力-速度关系可表示为压力上升最大速率与最大等容压力之比，希尔将该量描述为压力的最大比例上升速率，它类似于化学反应的速度常数。将该比值除以心室周长的估计值，可校正因初始纤维长度差异导致的变化。在11名正常受试者和46名心脏病患者进行左心导管检查期间，对该指标进行了评估。通过对心室压力脉冲进行电子微分获得压力上升最大速率，并假设心室为球形，根据指示剂冲洗法测量的容积计算心室周长。正常受试者的收缩性指数与二尖瓣狭窄、房间隔缺损或慢性肺部疾病（无左心室负荷过重的患者）患者的指数无差异。相比之下，左心室衰竭患者的指数比正常受试者的平均值低两个标准差以上。在心肌衰竭发作前，左心室压力或容量负荷过重的患者未出现这种降低。运动期间，无左心室疾病的患者该指数均匀上升，容量或压力负荷过重的代偿患者反应不一，左心室失代偿患者的指数几乎不变。无论患者状态如何，给予异丙肾上腺素或洋地黄均可导致收缩性增加。结论是，在心室生理学研究以及诊断和治疗决策中使用该指数是合理的。
