低温环境下家兔急性心肌缺血时心电图的变化木

目的：探讨低温环境下家兔急性心肌缺血时心电图的变化。方法：将56只家兔随机分为实验组和对照组，每组各28只。两组家兔均置于自然低温环境下（10℃、5℃、0℃、-5℃）暴露30～60min后做肢体导联心电图，分析心律失常发生情况，心率、ST段及T波的变化。结果：10℃、5℃及0℃自然低温环境下实验组心律失常阳性率与对照组比较，差异无统计学意义（P〉0．05）；-5℃自然低温环境下实验组心律失常阳性率高于对照组，差异有统计学意义（X^2=4．667，P〈0．05）。随着环境温度下降，实验组心律失常阳性率逐渐增加，与温度变化呈正相关（r=1．000，P〈0．01）。实验组和对照组心率均随着温度的下降逐渐减慢，与温度变化呈三次方函数关系CP〈0．001）；实验组与对照组心率比较，差异无统计学意义（P〉0．05）。实验组和对照组ST段压低及T波倒置幅度均随着温度的下降逐渐加深，与温度变化呈三次方函数关系（P〈0．001）；实验组与对照组ST段之间、T波之间比较，差异有统计学意义（P〈0．01）。结论：随着环境温度的下降，家兔的心肌缺血明显加重，心电活动紊乱，导致心律失常发生。

Electrocardiogram Changes of Rabbits with Acute Myocardial Ischemia in Low Temperature Environment

Objective： To study the electrocardiogram changes of rabbits with acute myocardial ischemia in low temperature environment. Method： 56 rabbits were randomly divided into experimental group and control group. There were 28 rabbits in each group. Limb lead electrocardiogram was done after two groups of rabbits were placed in the natural low temperature （10 ℃, 5 ℃, 0 ℃, -5 ℃ ） and exposed to 30-60 min, then arrhythmia, heart rate and changes of ST segment and T wave of both groups of rabbits were analyzed. Result： There was no statistical difference（P〉0.05） about the comparison of arrhythmia positive rate between experimental group and control group in the same natural low temperature（10 ℃, 5 ℃, 0 ℃）, but the arrhythmia positive rate of experimental group was significantly higher than that of control group in -5 ℃ environment（X^2=4.667, P〈0.05）. Along with the decrease of environmental temperature, the arrhythmia positive rate of experimental group was gradually increasing, and there was positive correlation with temperature changes（r=1.000, P〈0.01）. Along with the decrease of environmental temperature, the heart rates of experimental group and the control group were gradually slowing down, and the relationship between heart rate and temperature change showed cubic（P〈0.001）, but there was no significant difference of heart rate between experimental group and control group（P〉0.05）. Along with the decrease of environmental temperature, the range of ST segment depression and T wave inversion was gradually increasing, and its relationship with temperature change showed cubic（P〈0.001）. According to the respective comparison of ST segment and T wave between experimental group and control group, the difference was statistically significant（P〈0.01）. Conclusion： Along with the decrease of environmental temperature, myocardial ischemia of the rabbits with acnte myocardial ischemia is aggravated, whieh caused the disorders ofheart＇ s electricalactivities, thereby leading to arrhythmia.