Experiment Study Of Cardiac Resynchronization Pacing With Different Sites Combination On Chronic Ischemic Heart Failure

Chronic heart failure(CHF) has become a major problem whichthreatened human health and life In the field of cardiovascular disorders. It hascharacteristics of expensive economic cost, high hospitalization and mortalityrates. Despite important therapeutic advances with angiotensin convertingenzyme inhibitors(ACEI), angiotensin II–receptor blockers (ARB),beta-blockers and spironolactone, the prognosis of a quite number of patientswith chronic heart failure remains poor. The benefit of medical treatment cannot reverse the inevitable progression to heart failure that is refractory to drugtreatment.As the disorder progress, the quality of life and exercise toleranceofpatients deteriorate dramatically, and the rate of rehospitalizationincreases. Inrecent years,a series of nonpharmacologic therapies have been attempted forCHF patients who were refractory to drug treatment, such as cardiactransplantation, left ventricular assist devices, myocardioplasty andimplantable artificial heart. Of course, cardiac transplantation is considered theoptimal option, but is restricted simultaneously. It is against this backdrop oflimited resources, repulsion reaction and so on. With the rapid development ofpacing engineering, the indications of cardiac pacing have evolved.resynchronization therapy by means of biventricular pacing was proposedthrough a series of clinical exploration and studies. Primary studies haveconformed that biventricular pacing for patients with CHF showed a sustainedimprovement in terms of hemodynamics and clinical symptoms.Whereas, themost present studies focused on short-term clinical trials without animalexperiment evidences and differentiating etiology of CHF. Therefore, in theseries of the present study, the aim is to assess the effects of cardiacresynchronization pacing with different sites combination on cardiacperformance, ventricular remodeling, coronary circulation, myocardium 8英 文 摘 要oxygen metabolism and cardiac work efficiency in minipig models withchronic ischemic heart failure. And then, Cardiac resynchronization pacingmode with the best multisite combination will be selected. As a result, it willoffer experiment foundation for the pacing treatment of chronic ischemic heartfailure. The detailed methods and results of our study are as follows:Part one: The Model of Chronic Ischemic Heart Failure in Minipigs Objective: Stable large animal models of chronic ischemic heart failureare difficult to establish. Wuzhishan minipig was selected in this study due toits cardiovascular biological characteristics approximated to human being. Theaim was to establish a minipig model of stable chronic ischemic heart failureachieved by repetitive intracoronary(LAD) microspheres perfusion withcatheter-based techniques. Methods: A total of fifteen Wuzhishan minipigs(8 to 11 months old witha body weight of 20 to 30 kg) were used. The embolization solution wasprepared by suspending 0.1 g of compound plastic microspheres(meandiameter 100 m, ranged from 78 to 112 m) in 5ml of 0.9%physiological saline and 5ml of Ultravist 370 contrast medium.1 105 plasticmicrospheres in 1 ml suspension was obtained. The whole solution wascarefully votexed before intracoronary injection. All cardiac catheterizationswere performed under general anesthesia with sodium pentobarbital 20 mg/kgIV and sterile conditions. With Seldinger's technique and 4F Judkinsangiographic catheter(inner diameter 0.97mm),left ventriculogram andcoronary angiography(CAG)were performed in sequence by femoral approach.And then, the 4F angiographic catheter was positioned in left anteriordescending artery(LAD) by using special angiographic techniques. About 1105 plastic microspheres in 1 ml suspension were injected within 60 secondsevery time and above doses were given repeatedly at ten-minute intervals untilLVEDP maintained from 15mmHg to 18mmHg and TIMI flow was less...