氰化物对犬心肌收缩性能的影响

Effects of Cyanide Poisoning on Myocardial Contractibility in Dogs

本文运用直接测定心肌收缩力的方法,研究了氰化物对犬心肌收缩性能的影响。氰化钠(NaCN)2.5mg/kg经静脉于2min内输入中毒。结果表明,在中毒1min时,NaCN对心率(HR)的抑制作用明显,但对心肌收缩性能有兴奋作用。中毒1min后,动物体内NaCN增加,LVP及±dp/dt_(max)开始呈进行性下降,CMC下降不明显,提示此时心肌收缩已为无效。动物濒临死亡时,CMC及±dc/dt_(max)急剧下降,心电图表现为频发的室性早搏及室颤。实验证明,氰化物中毒对犬心肌收缩性能有较长时间的兴奋作用,但为无效兴奋,这种作用可能加重心律失常,导致动物心功能衰竭死亡。

The effects of cyanide poisoning on the contractibility of the cardiac muscle were observed after the dogs were infused intravenously with a lethal dose of NaCN (2.5 mg/kg) within 2 minutes through a cannulated femoral vein. Heart rate (HR) , left ventricular pressure (LVP) , the largest changing rate of LVP (LVP±dp/dtmax), cardiac muscle contractibility (CMC) , the largest changing rate of CMC (CMC±dc/dtmax) , and ECG changes were recorded. It was found that there was an initial excitatory response of cardiac functions in the first minute of NaCN infusion, and then a drastic cardiac failure occurred, which resulted in the rapid death of the dogs within 10 minutes after NaCN administration. The changes of myocardial contractibility were slower than those of .other cardiac parameters, which implies that cyanide can exert an excitation on the myocardium initially. Our results indicate that the effects of cyanide on myocardial contractibility may be one of the important factors to induce serious arrhythmia,which in turn results fatal cardiac failure.