Effects of organic solvents inhalation on left ventricular contractility

本文观察了麻醉犬吸入有机溶剂对左心室收缩力的影响。在急性吸入实验中，用1，1，1-三氯乙烷（1，1，1-TCE）、三氯乙烯、四氯乙烯、甲苯、间二甲苯和三氯三氟乙烷等有机溶剂，每吸入一次有机溶剂，由左心室压力的一阶导数得到的峰值dp/dt就降低一次。吸入高浓度1，1，1-TCE后，左室压力、dp/dt/P40和Vmax同时降低。同时记录的心率随着1，1，1-TCE浓度相对较低而增加，随着浓度升高而降低。观察到峰值dp/dt的增加或减少取决于右心房起搏引起的心率变化。因此，在起搏实验中的峰值dp/dt的下降程度进行了比较与非起搏实验。在较高浓度下，起搏期间峰值dp/dt的下降略小于非起搏实验。在随后的实验中，研究了在较高的1，1，1-TCE浓度下峰值dp/dt降低对心脏的直接影响。比较迷走神经交感神经完整组和失神经组的dp/dt峰值程度。两组吸入1，1，1-TCE后dp/dt峰值下降程度相同，提示吸入有机溶剂后左室等容收缩期收缩力下降，并提示心率及对心脏的直接影响可能与吸入有机溶剂后左室收缩力下降有关。

Effects of organic solvents inhalation on left ventricular contractility were studied in anesthetized dogs. 1,1,1-trichloroethane(1,1,1-TCE), trichloroethylene, tetrachloroethylene, toluene, m-xylene and trichloro-trifluoroethane were used in this experiments.In acute inhalation experiments, peak dp/dt that obtained by the first derivative of the left ventricular pressure decreased follwing each organic solvent inhalation. Moreover, left ventricular pressure, dp/dt/P40 and V max decreased simultaneously following 1,1,1-TCE inhalation of higher concentrations. Heart rate recorded simultaneously increased with relatively low 1,1,1-TCE concentrations and decreased with higher concentrations. Increase or decrease in peak dp/dt was observed to be dependent on changes in heart rate induced by right atrial pacing. Thus, the degree of the decrease in peak dp/dt during pacing experiments was compared with those of nonpacing experiments. At higher concentrations, the decreases in peak dp/dt during pacing was slightly less than in the nonpacing experiments. In a subsequent experiments, direct effect to the heart in the decrease in peak dp/dt was investigated following higher 1,1,1-TCE concentrations. Degrees of the peak dp/dt was compared between groups with vagi-sympsthetic intact and groups with denernation. degree of the decreases in peak dp/dt were same in both groups following 1,1,1-TCE inhalation.It is suggested that left ventricular contractility in the period of isovolumetric contraction decreased following organic solvents inhalation, and furtuer suggested that heart rate and direct effects to the heart may be related to the decrease in left ventricular contractility following organic solvants inhalation.