The Value And Effect Of Dobutamine Stress Echocardiography On Hibernating Myocardium And Coronary Hemodynamic Indexes In Domestic Swines

Part one: The Experimental Study Of The Acute Hibernating Myocardium.The Effect Of Dobutamine Stress Echocardiography On HibernatingMyocardium And CoronaryHemodynamic IndexesOBJECTIVE: To establish an animal model of acute hibernating myocardium(AHM), to investigate responsed classification of left ventricular wall movementand the efficiency and the mechanism of dobutamine stress echocardiography (DSE)in detecting AHM; to observe the changes of coronary hemodynamic andelectrocardiographic indexes in AHM model and during DSE;to investigate therelationship between these indexes and the status of AHM; to determine thecharacters of wall movement in baseline and during DSE by Doppler tissueimaging(DTI) and the potential of DTI in detecting AHM.MATERIALS AND METHODS: Thirteen little domestic Chinese swine wereincluded , we established the model of AHM by interventional method withangioplasty ballon through right coronary artery(closed-chest),then theyunderwent DSE (0-40mg/kg.min),the segments which appeared biaphasic response wereconsidered AHM; Intracoronary Doppler guidewire were used to measure average peakvelocity (APV),diastolic systolic velocity ratio (DSVR)and coronary flow velocityreserve (CFVR) in AHM model and in each stage of DSE;at the same time,systolicblood pressure (SBP),diastolic blood pressure (DBP), Heart rate(HR) and HR-SPdouble products(RPP) were recorded; Electrocardiogram were recorded to examinethe changes of QRS amplitude and QT dispersion (QTd) in AHM model and in eachstage of DSE. Systolic peak velocity(Vs), early diastic peak velocity(Ve) and enddiastolic peak velocity(Va) of left ventricular wall motion were determined byDTI in normal status, AHM model and the peak dose stage of DSE. After all parameterswere achieved, regional myocardium were reperfused through balloon deflationtwenty minutes later, APV, CFVR, QRS, QTd ect. were recorded once again to evaluatethe effect of repurfusion on these parameters. At the end, animals were killedby intravenous injection of 10% potassium chlorid, the heart was stained with TTCand the histomography changes of AHM cells were assessed by microscope.RESULTS: 1. one of thirteen animals died for deep anesthesia, two died forventricular fibrillation, the rest were established the model of AHM successfully.The success percentage rate is 76.92%,it's higher than the method of open-chestreported by literature. 2. Pathological results: myocardium necrosis were not复旦大学博士论文— 7 —found, swelled nucleolus and blood capillary of dilatation and hyperemia werefound under the microscope. 3. Among 160 segments, 105 segments were normal inwall movement(105/160,65.63%), 33 segments were hypokinesia(33/160,20.63%), 22were akinesia(22/160,13.75%), no one segments appeared dyskinesia; biaphasicresponse appeared in 41 segments of 55 abnormal segments during DSE. The positivepercentage rate of DSE in detecting AHM was 74.54%. The incidence of biaphasicresponse was higher in hypokinesia segments than in akinesia segments(84.85% vs59.10% , P < 0.05 = . 4. APV, CFVR of the distal to the stenosis decreasedsignificantly in AHM model(4.56±2.23 vs 22.13±7.99, 0.95±0.22 vs 2.37±0.42;P<0.01=, while partially improved after reperfusion(10.14±2.11 vs 4.56±2.23,1.34±0.19 vs 0.95±0.22; P<0.01=, DSVR didn't change obviously. APV, DSVR,SBP, DBP, HR, RPP were all increased during DSE, but APV was increased at lowerdose stage than other indexes. △APV (difference between baseline and peak dosestage of DSE) correlated to the amount of AHM segments positively(r=0.66,P<0.05=. 5.QTd was increased significantly in AHM model(68.75±5.33 vs 25.00±1.77; P<0.05), it correlated to the amount of AHM segments negatively(r=-0.64,P <0.05=, it recovered completely after reperfusion. QTd was appearedbiaphasic change during DSE. Whether in AHM or during DSE, QRS amplitude didn'tchange obviously. 6.In normal subjects, Vs of left ventricular wall had suchcharacters as: base region >middl...