中文摘要：

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。

英文摘要：

Objective To utilize velocity vector imaging （VVI） in analyzing regional myocardium function within 30 minutes before and after myocardial ischemia induced by occlusion of coronary artery in New Zealand white rabbits and to evaluate the changes of longitudinal and brachydiagonal segmental left ventricular（LV） systolic function in rabbits with acute myocardial ischemia. Methods Thirty New Zealand white rabbits were divided into groups of myocardial ischemia and sham operation. All rabbits were performed by echocardiography before the operation and after the operation within 30 minutes and dynamic cardiac images were collected. All of these images were analyzed off-line using VVI software. These LV myocardium longitudinal and brachydiagonal VVI parameters：systolic velocity（Vs）,systolic strain（Ss） and systolic strain rate （SRs） were assessed and analyzed. Results Compared with those before operation and sham operation group in ischemia condition,the longitudinal Vs were lower in the apical segments of anteroseptum and posterior wall （P0.05）; the longitudinal Ss,SRs were lower in the middle and apical segments of anteroseptum wall,the apical segment of posterior wall （P0.05）; the radial Vs were lower in the basal segments of anterior and lateral wall,the middle segments of anteroseptum,anterior and lateral wall,all apical segments（P0.05）; the circumferential Ss and SRs were lower in the basal segments of anteroseptum,anterior and lateral wall,the middle segment of anteroseptum,anterior,lateral and posterior wall and all apical segments（P0.05）. Conclusions The regional LV myocardial systolic function decrease after acute myocardial ischemia in longitudinal and brachydiagonal directions. The VVI is a novel noninvasive tool to quantitatively and objectively assess LV regional myocardial systolic function,which could provide another useful method for early diagnosis of acute myocardial ischemia.