Studies Of Establishing Animal Model And Mechanism Of Ventricular Tachycarida With Ishemia Cardiomyopathy And Mapping And Catheter Ablation Of Ventricular Tachycardia Using Non-contact Mapping System

BackgroundsIschemia heart disease is the most common cause of sustained monomorpic ventricular tachycardia (VT). Among of the management of this arrhythmia , antiarrhythmia drugs have poor efficacy at suppressing VT and have been associated with long-term side effects including proarrhythmia and excess mortality. Although ICD have been shown to significantly reduce arrhythmic deaths, these devices do not affect the occurrence or frequency of VT. Furthmore, due to their high cost, an ICD is not an option for many patients. The major drawback to arrhythmia surgery is the operative morbidity and mortality. With the success of radiofrequency catheter ablation (RFCA) in supreventricular tachycardia and idiopathic ventricular tachycardia, ablation of VT with organic heart disease especially ischemia heart disease is becoming the major area of study. RFCA offers hope of preventing VT recurrence, avoiding antiarrhythmic drug toxicities, and the risks of surgery. However, RF ablation of VT due to ischemia heart disease continues to be one of the most challenging procedures in clinical elsctrophysiology. Because of the limitation of conventional mapping methods, the successful rate of ablation of the VT is lower. A number of technological innovations including non-contact mapping system may improve the ease and efficacy of catheter ablation.The mechanism of VT due to ischemia heart disease is not clear and the electrophysiological mechanism is very complex. Furtherinvestigation about cardiac remodeling, mechanism of pothophysiology and the actions of these changes in resulting in ventricular arrhythmia and cardiac function after myocardial infarction are needed. Ionic channels of myocardium play a key role in maintaining normal heart function. Nearly all heart disease is related to the abnomality of ionic channels. Partial studies have certified that characteristic of ionic channels and expression of these ionic channel genes had some changes in the course of cardial remodeling after experimental MI. There are many controvert about ionic channel how to change and what exact actions in causing ventricular arrhythmia. Studies about them need to go step further. Objective(1) To develop a close-chest pig model of sustained monomorphic ventricular tachycardia after myocardia infarction and to investigate induce method and successful rate of inducing VT in experimental MI model.(2) Using monophasic action potential (MAP) recording technique, we observe the changes of MAP and effective refrectory period (ERP) in the porcine model of healed myocardial infarction and investigate the electric remodeling and electrophysiologic mechanism of sustained monomorphic ventricular tachycardia(3) Using the technique of semiquantitative reverse transcriptase- polymerase chain reaction (RT-PCR), we research the alterations of the expression of three potassium channel subunits and connexin43 gene after experimental myocardial infarction and discuss the cellular and molecular bases of arrhythmias in the postinfarction remodeled ventricular myocardium. The molecular mechanism of post-Mi ventricular arrhythmias is discussed with the research.(4) On the basis of establishing the model of sustained monomorphic ventricualr tachycardia of healed myocardial infarction, we investigate the accuracy of scar mapping and navigation of thenoncontact mapping system through correlation with pathology analysis. We also explore the electrophysiologic mechanisms and methods of mapping and catheter ablation of ventricular tachycardia in the porcine model of healed infarction using noncontact mapping system (EnSite 3000 system).(5) To assess the clinical utility and value of EnSite 3000 system for mapping and radiofrequency catheter ablation of refractory ventricular tachycardias include organic heart disease.Methods(1) Nineteen pigs that weighed 30 ?5kg were studied. Thirteen pigs underwent coronary artery angiogr...