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目的建立新西兰大白兔急性心肌缺血的动物模型,应用速度向量成像(VVI)技术分析急性心肌缺血状态下左心室长轴和短轴方向上各节段局部心肌收缩功能的变化特点。方法新西兰大白兔30只,随机分为冠状动脉结扎组和假手术组,于术前和术后30min内行超声心动图检查并采集动态图像,脱机行VVI分析,测量左心室心肌各节段长轴和短轴方向上的VVI参数:收缩期峰值运动速度(Vs)、收缩期峰值应变(Ss)、收缩期峰值应变率(SRs),行统计学分析。结果心肌缺血后,分别与术前及与假手术组比较,长轴方向上,前间隔心尖段与后壁心尖段的Vs明显减低;前间隔中间段、心尖段与后壁心尖段Ss、SRs明显减低,差异均有统计学意义(P<0.05);短轴方向上,前壁、侧壁的基底段,前间隔、前壁、侧壁的中间段和心尖水平的各节段的Vs明显减低;前间隔、前壁、侧壁的基底段,前间隔、前壁、侧壁、后壁的中间段以及心尖水平各节段的Ss、SRs明显减低,差异均有统计学意义(P<0.05)。结论急性心肌缺血后左心室支供血节段及部分相邻节段的长轴及短轴局部心肌收缩功能减低。VVI技术能够客观、准确的检测实验兔心肌长轴和短轴方向上局部运动功能的微小变化,为急性心肌缺血的早期诊断提供了一种新的无创的、可靠的定量工具。
OBJECTIVE: To establish an animal model of acute myocardial ischemia in rabbits of New Zealand white rabbits. The changes of local myocardial contractile function in each segment of left and right ventricular in acute myocardial ischemia were analyzed by velocity vector imaging (VVI). Methods Thirty New Zealand white rabbits were randomly divided into coronary ligation group and sham operation group. Echocardiography and dynamic images were taken before and 30 minutes after operation. VVI analysis was performed offline to measure the length of each segment of left ventricular myocardium VVI parameters in axial and short axis directions: peak systolic velocity (Vs), systolic peak strain (Ss), systolic peak strain rate (SRs), and statistical analysis. Results After myocardial ischemia, the Vs of the apical and posterior apical segments in the long axis were significantly decreased compared with those in the preoperative and sham-operated groups respectively. In the middle segment of the anterior segment, the apical and posterior apical segment Ss, SRs were significantly decreased (P <0.05). In the direction of short axis, the anterior segment, anterior segment, anteroseptal, anterior segment, middle segment of lateral wall and apical segment (P <0.05). The Ss and SRs of the anterior septum, the anterior septum, the anterior septum, the anterior wall, the lateral wall, the posterior wall and the apex of the apical segment were significantly decreased (P <0.05). Conclusion The myocardial systolic and diastolic function of the left ventricular branches and some adjacent segments of the left ventricular branches after acute myocardial ischemia decreased. VVI technology can objectively and accurately detect small changes of local motor function in the direction of long-axis and short-axis of myocardium in rabbits, which provides a new noninvasive and reliable quantitative tool for the early diagnosis of acute myocardial ischemia.