Effect Of Selective Ablation Of Marshall Ligament On Ventricular Arrhythmias In Dogs With Acute Myocardial Infarction

Malignant ventricular arrhythmia is the direct and main cause of sudden death in patients with myocardial infarction.Sympathetic activation is an important factor to induce malignant arrhythmia after myocardial infarction.As anatomical results of our present study,Marshall ligament is an important channel for the left stellate ganglion to dominate the ventricle,and Destruction of Marshall ligament can eliminate the effect of left stellate ganglion stimulation on the ventricles.Marshall ligament ablation of the early stage of the study group to prevent long QT syndrome sudden death has been initially successful.In this study,we constructed an animal model of acute myocardial infarction in order to observe the effects of Marshall ligament on the electrophysiological properties and ventricular arrhythmias after myocardial infarction.The purpose of this study was to investigate the efficacy and safety of ablation of Marshall ligament to prevent malignant ventricular arrhythmia after myocardial infarction.Part I:Effects of the distal segment of the Marshall ligament ablation on the activity and function of the left stellate ganglionObjective:Objective to investigate the effects of distal segment of Marshall ligament on the activity and function of left stellate ganglion.Methods:12 adult healthy male dogs were selected,and the distal segment of Marshall ligament was selectively ablated.Then the activity of left stellate ganglion was recorded before and after ablation.High frequency electrical stimulation of the left stellate ganglion was performed before and after ablation(20Hz,0.1ms,5V?30V).The changes of blood pressure were recorded.The ratio of the maximal change of blood pressure was taken as the ordinate and the stimulation voltage was the abscissa.Results:There was no significant difference in the frequency and amplitude of left stellate ganglion discharges before and after the distal segment of the Marshall ligament(P>0.05).Stimulation of the left stellate ganglion before and after ablation both caused an increase in blood pressure,but After ablation,the blood pressure increased more slowly than before ablation.Conclusion:Ablation of the distal segment of the Marshall ligament could reduce the function of the left stellate ganglion,but had no significant effect on the activity of the left stellate ganglion.Part ?:Effect of selective ablation of Marshall ligament on ventricular arrhythmias in dogs with acute myocardial infarction Objective:Objective to investigate the effect of selective ablation of Marshall ligament on ventricular arrhythmias after myocardial infarction in dogs.Methods:In the first part of the 12 dogs before and after ablation,the ERP values of left and right heart were measured before and after ablation,and the changes of ERP value before and after ablation were compared.The other 14 healthy adult male dogs were randomly divided into two groups:the first group,7 dogs,control group only for myocardial infarction treatment;the second group,7 dogs,the ablation group,MI +LOMLSPV ablation for treatment,the number of ventricular arrhythmias in one hour were compared between the two groups after myocardial infarction.Results:(1)ERP:Compared with before ablation,the ERP value was significantly prolonged after ablation.The mean value of in the right heart base(RVB)was 164±22,and the mean value after ablation was 180±30(P<0.05).The mean value of in the right heart middle(RVM)was 167±24,and the mean value after ablation was 180±29(P<0.05).The mean value of in the right heart apex(RVA)was 173±24,and the mean value after ablation was 181±30(P<0.05).The mean value of in the left heart base(LVB)was 183±37,and the mean value after ablation was 190±40(P<0.05).The mean value of in the left heart middle(1VM)was 176±30,and the mean value after ablation was 187±34(P<0.05).The mean value of in the left heart apex(LVA)was 174±27,and the mean value after ablation was 180±30(P<0.05).(2)Ventricular arrhythmia event:Compared with the first group,the incidence of ventricular arrhythmias in the second groups was significantly reduced.In the control group,the number of premature ventricular beats is 278.29±205.73,and the average number of ventricular premature beats in ablation group is 23.43±17.63(P<0.05).The mean number of paired ventricular premature beats is 9.29±7.11,and the number in ablation group is 0.57±0.53(P<0.05).The mean number of ventricular tachycardia occurred in the control group is 7.75±8.73,and the number in ablation group is 0.43±1.13(P<0.05).The control group and the ablation group both had a ventricular fibrillation.Conclusion:Ablation of the LSPV segment of the Marshall ligament can prolong the effective refractory period(ERP)of the canine model,change the electrophysiological characteristics of the ventricle,and reduce the occurrence of ventricular arrhythmias in the canine model of acute myocardial infarction.And the possible mechanism of anti arrhythmia is to block the sympathetic pathway between the left stellate ganglion and the ventricle.