Smith N T, Ingels N B, Daughters G T, Wexler L
Anesth Analg. 1980 Mar;59(3):178-85.
We investigated the possibility that myocardial asynergy (dyscoordinate contraction) is a contributing mechanism to the impairment of cardiac function produced by halothane. Coronary cineangiograms were performed in seven dogs, awake and at 1, 2, and 3 MAC halothane. The relative motions between four arterial bifurcations (six segments) were plotted as an indication of changing ventricular dimensions. To quantitate ventricular asynergy, we calculated anisotropy (AI) and asynchrony (AS), the coefficient of variation of mean shortening (S-) and of mean time to half shortening (T-50), respectively, of the six segments. From these a myocardial performance index (MPI) was derived: MPI = S-/AI + T-50 + AS. In general, S- and MPI decreased with increasing halothane concentration. Anisotropy showed a trend, although usually insignificant, toward increasing, while AS did not change. These observations have two implications. First, asynergy of contraction contributes little, if anything, to halothane-induced impairment of myocardial performance. Second, changes in measurements of intact cardiac performance, such as dP/dtmax, may be reasonably valid during halothane, provided loading conditions are taken into account.
我们研究了心肌运动不协调（收缩不协调）是否是氟烷导致心功能损害的一种促成机制。对7只清醒的狗以及处于1、2和3倍最低肺泡有效浓度（MAC）氟烷状态下的狗进行了冠状动脉电影血管造影。绘制四个动脉分支（六个节段）之间的相对运动，以指示心室大小的变化。为了量化心室运动不协调，我们分别计算了六个节段平均缩短率（S-）和平均缩短至一半时间（T-50）的变异系数各向异性（AI）和异步性（AS）。由此得出心肌性能指数（MPI）：MPI = S-/AI + T-50 + AS。一般来说，S-和MPI随着氟烷浓度的增加而降低。各向异性呈增加趋势，尽管通常不显著，而异步性没有变化。这些观察结果有两个含义。第一，收缩不协调对氟烷引起的心肌性能损害几乎没有作用（如果有作用的话）。第二，如果考虑到负荷条件，在氟烷作用期间，诸如最大dp/dt等完整心脏性能测量值的变化可能是相当有效的。
