The Value Of Quantitative Tissue Velocity Imaging And Cardiac Troponin I In Evaluation Of The Left Ventricle Function Of Different Geometric Patterns In Rabbits With Hyperthyroid Cardiomyopathy

Objective:1.To evaluate the left ventricle function of different geometic patternsin rabbits with hyperthyroid cardiomyopathy by quantitative tissue velocity imaging(QTVI).2.To study the correlation of serum cardiac troponin I (cTnI) with cardiac functionin different geometric patterns of left ventricle in rabbits with hyperthyroidcardiomyopathy.Methods:Part one:Thirty New Zealand purebred rabbits were randomly dividedinto experimental group(n=20) and control group(n=10).Hyperthyroidism models wereestablished by peritoneal injection of levothyroxine(L-Thy) in experimental group[45μg/(kg·d)].The same dose of saline was given to rabbits in control group for4weeks.QTVI and conventional echocardiographic parameters were obtained at thebeginning day and1st,2nd,4thweek in two groups,these parameters were as follows:leftventricular end diastolic diameter(LVDd),interventricular septal thickness at enddiastole(IVSTd),left ventricular inferolateral wall thickness at end diastole(IWTd),leftventricular ejection fraction(LVEF),left ventricular fraction shortening(LVFS),Evelocity(E),systolic peak velocity(Vs),systolic acceleration(a),early diastolic peakvelocity(Ve) and E/Ve.According to the changes of conventional parameters,the rabbitsof experimental group were divided into two subgroups:concentric hypertrophy(CH)subgroup and eccentric hypertrophy(EH) subgroup.Part two:The animal,group and heart function parameters were the same as thepart one.Hitachi7600automatic biochemical analyzer and diagnostic kits were used todetect cTnI in rabbits with hyperthyroid cardiomyopathy. Results:Part one:At the first week,LVEF,LVFS,E,average Vs and a increasedobviously than before injection in experimental group(P<0.01).At the secondweek,LVDd,IWTd, IVSTd,RWT and LVMI increased obviously than before injectionin experimental group and control group(P<0.05),and the average mitral annular Ve wassignificantly lower(P<0.01).At the fourth week,LVEF、LVFS、average Vs、average aand average Ve decreased significantly compared with those before injection(P<0.01,P<0.05).Com-pared with control group,the average Ve significantly decreasedin CH subgroup (P<0.01),while LVEF,LVFS,average Vs,average a and average Vesignificantly decreased in EH subgroup(P<0.01).Part two:The cTnI in blood of CH subgroup was conspicuously higher than that ofthe control group(P<0.01).The cTnI in blood of EH subgroup was conspicuously higherthan that of the control group and CH subgroup(P<0.01).Vs and Ve had negativecorrelation with serum cTnI in blood(P<0.01).LVMI had positive correlation withserum cTnI in blood(P<0.01).Conclusion:1.QTVI is valuable in the assessment of establishing levothyroxine-induced cardiomyopathy models in rabbits.QTVI can accurately assess the left ventriclefunction of different geometic patterns in rabbits with hyperthyroid cardiomyopathy.2.The rise of serum in blood cTnI is different in different geometric patterns inrabbits with hyperthyroid cardiomyopathy.And the rise of serum cTnI is closely relatedto cardiac function in rabbits with hyperthyroid cardiomyopathy.