| Objective:The present study is to investigate the effect of actue myoeardial ischemia to Tpeak-Tend interval of surface eleetroeardiogram(ECG) and the correlation between Tpeak-Tend interval,Tp-Te/(?),Tp-Te/QT ratio and ventricular fibrillation in rabbits with early acute myocardial infarction in order to provide for warning indexes based on the occurrence of ventricular fibrillation.Method:Fifty healthy rabbits of both sexes,weighing 2.0-2.6kg, were enrolled in this study. Rabbits were randomly divided into experimental group(n=40) and control group(n=10).All rabbits were injected with 20% ethyl carbonate (5ml/kg) via ear vein and were performed thoracotomy. Left ventricular branch of coronary artery of rabbits in the experimental group were ligated to copy the model of acute myocardial infarction.The 9 leads ECG before open-chest, before ligation and the 9 leads ECG after ligation 30 minutes were reeorded. The rabbits were divided into the ventricular fibrillation group and the non-ventricular fibrillation group according to whether occurred ventricular fibrillation within coronary artery ligation 30 minutes.The rabbits in control group were opened-chest, threaded without ligation and the 9 leads ECG before open-chest and after open-chest 30 minutes were recorded.Tp-Te interval, QT interval and R-R interval in ECG was measured in order to analyse QT interval, Tp-Te interval, Tp-Te/(?), corrected QT interval (QTc) and Tp-Te/QT ratio.Result: 1. The R-R interval, QT interval, Tp-Te interval of the control group after surgery was longer versus before surgery, but the difference was not statistically significant (P> 0.05).2. The Tp-Te interval and Tp-Te/(?) of the ventricular fibrillation group was the longest and the Tp-Te/QT ratio was the maximum at the time of before ventricular fibrillation occurred.3 rabbits of the ventricular fibrillation group occurred ventricular fibrillation in 20-25min period,2 rabbits occured ventricular fibrillation in less than 20min period and a rabbit occurred ventricular fibrillation in 25-30min period after coronary artery ligation.The Tp-Te interval and Tp-Te/(?) of rabbits in the non-ventricular fibrillation group was extended trend after left ventricular branch of coronary artery ligation and the Tp-Te interval and Tp-Te/(?) of of rabbits in the non-ventricular fibrillation group rise to maximum at 25min after ligation.3. After coronary artery ligation the Tp-Te interval of rabbits in the experimental group was significantly longer than that of the control group, the difference was statistically significant (41.515±4.048 compared with 33.750±4.432, P<0.05).After coronary artery ligation the Tp-Te/(?) of rabbits in the experimental group was significantly longer than that of the control group, the difference was statistically significant (81.823±4.816 compared with 68.655±6.890, P<0.05).4. After coronary artery ligation the Tp-Te interval of rabbits in the ventricular fibrillation group was longer than that of the non-ventricular fibrillation group, but the difference was not statistically significant (44.167±4.916 compared with 40.926±3.679, P> 0.05).After coronary artery ligation the Tp-Te/(?) of rabbits in the ventricular fibrillation group was significantly longer than that of the non-ventricular fibrillation group, the difference was statistically significant (86.191±4.524 compared with 80.852±4.386, P<0.05).After coronary artery ligation the Tp-Te/QT ratio of rabbits in the ventricular fibrillation group was significantly longer than that of the non-ventricular fibrillation group, the difference was statistically significant (0.289±0.013 compared with 0.275±0.011, P<0.05).Conclution:1. Acute myocardial ischemia can cause Tp-Te interval prolongation.2. Tp-Te/(?) and Tp-Te/QT ratio can be used as non-invasive indexes of warning ventricular fibrillation occurred in rabbits with early acute myocardial infarction.3. Tp-Te/QT ratio can be used as an index of reflect the Tp-Te interval relative size by eliminate heart rate influence. |
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