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

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.

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

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.