超声斑点追踪显像评估压力超负荷性左心室肥厚兔的左心室功能

Evaluation of left ventricular performance with speckle tracking echocardiography in rabbit models of pressure-overload left ventricular hypertrophy

目的应用超声斑点追踪显像(STE)评价腹主动脉缩窄性高血压左心室肥厚兔模型的左心室纵向、径向、圆周应变及扭转运动,探讨其与心肌纤维化的关系。方法 22只雄性新西兰兔随机分为两组:左心室肥厚组(LVH组,n=12)、假手术组(对照组,n=10)。建立左心室肥厚兔模型,术后8周应用STE技术测量左心室纵向、径向、圆周应变及左心室扭转相关参数,并行左心室导管及心肌病理学检查。结果 LVH组纵向应变(LS)减低,左心室扭转角度峰值(Ptw)、扭转速度峰值(PTV)、解旋速度峰值(PUTV)增加,扭转角度达峰时间(tPtw)、解旋速度达峰时间(tPUTV)延迟,等容解旋率(IUR)减低,解旋减半时间(UHT)延长,差异均有统计学意义(P均<0.01)。LVH组心肌平均胶原容积分数(CVF)与LS呈正相关(r=0.63,P=0.038)。结论 STE可准确评价左心室肥厚兔的左心室功能,其中LS可反映心肌纤维化程度。

Objective To analyze the left ventricular longitudinal strain （LS）,radial strain （RS）,circumferential strain （CS） and twist motion with speckle tracking echocardiography （STE） in rabbit models of pressure-overload myocardial hypertrophy,and to evaluate their association with myocardial fibrosis. Methods Twenty-two male New Zealand rabbits were randomly divided into two groups,i.e. left ventricular hypertrophy group （LVH group,n=12） and sham-operation group（control group,n=10）. Left ventricular hypertrophy was induced by suprarenal abdominal aortic constriction for eight weeks. Then LS,RS,CS and twist-related parameters were measured with STE,and left ventricular catheterization and myocardial pathological examination were performed. Results Compared with sham-operation group,left ventricular LS decreased,peak twist angle,peak twisting velocity,peak untwisting velocity increased,time to peak twist and peak untwisting velocity delayed,isovolumic untwisting rate decreased,untwisting half-time was prolonged in LVH group （all P〈0.01）. Collagen volume fraction （CVF） of LVH group was correlated positively to LS （r=0.63,P=0.038）. Conclusion STE is useful in evaluating left ventricular performance in rabbit models of left ventricular hypertrophy,and LS may suggest the degree of myocardial fibrosis.