ABSTRACT
ObjectiveTo assess the value of quantitative tissue velocity imaging (QTVI) in monitoring the establishment of levothyroxine-induced cardiomyopathy models on rabbits.MethodsThirty New Zealand purebred rabbits were divided into experimental group (n=20) and control group (n= 10).Hyperthyroidism models were established by peritoneal injection of levothyroxine (L-Thy) in experimental group (45 μg/ [kg · d]).The same dose of saline was given to rabbits in control group for 4 weeks.QTVI and conventional echocardiographic parameters were obtained at the beginning day and 1,2,4 weeks in two groups.According to the changes of ultrasound parameters,the rabbits of experimental group were divided into two subgroups:Concentric hypertrophy (CH) subgroup and eccentric hypertrophy (EH) subgroup.ResultsAt the first week,left ventricular ejection fraction (LVEF),fractional shortening (LVFS),mitral inflow peak velocity (E),average mitral annularsystolic peak velocity (Vs) and acceleration (a) increased obviously than before injection in experimental group (P＜0.01).At the second week,posterior wall thickness at end diastole (PWTd),interventricular septal thickness at end diastole (IVSTd) and left ventricular mass index (LVMI) increased obviously than before injection in experimental group and control group (P＜0.05),and the average mitral annular early diastolic velocity (Ve) was significantly lower (P＜0.01).Compared with control group,the average Ve was significantly lower in CH subgroup (P＜0.01),while LVEF,LVFS,average Vs,a and average Ve were significantly lower in EH subgroup (P＜0.01).ConclusionQTVI is valuable in the assessment of establishing levothyroxine-induced cardiomyopathy models on rabbits.
