低温低氧对实验性心肌缺血家兔心电图的影响效应

摘要

背景:在某些情况下,低温与低氧有交互影响的作用,缺氧和低温复合因素对心肌缺血的心电图也会产生较大的影响.目的:探讨急性低氧加低温两个因素共同作用对正常家兔和心肌缺血家兔心电图的影响效应.设计:完全随机分组设计,对照实验.单位:右江民族医学院应用生理教研室.材料:实验于2002-07/12在右江民族医学院应用生理研究室完成.选用健康家兔32只.采用随机数字法将实验家兔分为4组:对照组、低温低氧组、低温低氧假心肌缺血组、低温低氧心肌缺血组,每组8只.方法:①低温低氧心肌缺血组家兔双重结扎冠状动脉前降支;低温低氧假心肌缺血组方法同低温低氧心肌缺血组,但只分离冠状动脉前降支穿线,不结扎.②将低温低氧组、低温低氧心肌缺血组和低温低氧假心肌缺血组家兔置于低温[(-10±2)℃]和低氧(含氧体积分数0.085)冷柜中30 min,然后测定各组心电图的变化.③计量资料差异性比较采用单因素方差分析.主要观察指标:低温低氧对正常和心肌缺血家兔心电图检测结果的影响.结果:家兔32只均进入结果分析.①低温低氧组家兔心率慢于对照组(P＜0.05),P波电压、ST段电压和R波电压均明显高于对照组(P＜0.05～0.01);T波电压低于对照组(P＜0.05);P波时间、PR间期、QRS间期和QT间期明显长于对照组(P＜0.05).②低温低氧心肌缺血组家兔心率慢于对照组(P＜0.05);P波电压、ST段电压、T波电压和R波电压均明显高于对照组(P＜0.01),QRS间期和QT间期明显长于对照组(P＜0.01,0.05),S波深度明显大于对照组(P＜0.05).③低温低氧心肌缺血组家兔ST段电压和T波电压明显高于低温低氧假心肌缺血组和低温低氧组(P＜0.01,0.05).结论:低温低氧对正常家兔的心电图有明显影响,对心肌缺血家兔的心电图影响更大,说明急性低温低氧双重作用可加重原有心肌缺血的发展.%BACKGROUND: There are interactions between low temperature and hypoxia under certain conditions, and the compound factors of hypoxia and low temperature also have great influence on the electrocardiogram (ECG)of myocardial ischemia.OBJECTIVE: To probe into the effect of the combined action of acute hypoxia and low temperature on the electrocardiogram (ECG) of normal rabbits and those with myocardial ischemia.DESIGN: A completely randomized and grouped design and control study.SETTING: Staff Room of Applied Psychology, Youjiang Medical College of NationalitiesMATERIALS: The experiment was carried out in the Department of Applied Physiology, Youjiang Medical College for Nationalities from July to December 2002. Thirty-two healthy rabbits were divided into 4 groups according to the method of random number table with 8 rabbits in each group: control group, low temperature and hypoxia group, low temperature and hypoxia+sham myocardial ischemia group, low temperature and hypoxia+myocardial ischemia group.myocardial ischemia group were treated with double ligation of anterior descending coronary artery, and those in the low temperature and hypoxia+sham myocardial ischemia group received the same treatment, but anterior descending coronary artery was only isolated and put through with thread low temperature and hypoxia+sham myocardial ischemia group, low temperature and hypoxia+myocardial ischemia group were placed in the cold cabinet of low temperature [(-10±2) ℃] and hypoxia (the volume fraction of oxygen was 0.085) for 30 minutes, and the changes of ECG in the the differences of the measured data.MAIN OUTCOME MEASURES: The effects of low temperature and hypoxia on the detected results of ECG of normal rabbits and those with myocardial ischemia were observed.The heart rate in the low temperature and hypoxia group was slower than that in the control group (P ＜ 0.05), the voltage of P wave, voltage of ST segment and voltage of R wave were all obviously higher than those in the control group (P ＜ 0.05-0.01), the voltage of T wave was lower than that in the control group (P ＜ 0.05), the time of P wave, PR interval,QRS interval and QT interval were obviously longer than those in the hypoxia+myocardial ischemia group was slower than that in the control group (P ＜ 0.05), the voltage of P wave, voltage of ST segment, voltage of T wave and voltage of R wave were all obviously higher than those in the control group (P ＜ 0.01), the QRS interval and QT interval were obviously longer than those in the control group (P ＜ 0.05), and the depth of S wave age of ST segment and voltage of T wave were all obviously higher in the low temperature and hypoxia+myocardial ischemia group than in the low temperature and hypoxia+sham myocardial ischemia group and low temperature and hypoxia group (P ＜ 0.01, 0.05).CONCLUSION: Low temperature and hypoxia have obvious influence on the ECG of normal rabbits, and have greater influence on the ECG of the rabbits with myocardial ischemia and it is then indicated that the double effects of acute low temperature and hypoxia can aggravate the development of original myocardial ischemia.