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目的探讨急性心肌梗死(心梗)后左室收缩期局域心肌的应变率特征是否能准确地显示左心室收缩运动的特点及其临床意义,探求评价局域心肌收缩功能的合理量化指标。方法24条健康杂种犬,麻醉后开胸,结扎冠状动脉左前降支近端。采集心梗前后3个完整心动周期的心肌组织速度图像,使用数字化超声工作站离线分析左室各节段长轴方向上心肌应变率曲线在收缩期变化特征。结果心梗后受累节段收缩期应变率峰值与梗死前相应节段相比明显减低(P<0.05)。结论应变率能敏感、直观、无创地定量评价局域心肌收缩功能的异常,可能为心肌局域性缺血或梗死提供更加早期的、客观的诊断信息。
Objective To investigate whether the strain rate characteristic of left ventricular systolic regional myocardium after acute myocardial infarction (AMI) can accurately show the characteristics and clinical significance of left ventricular systolic motion and to explore a reasonable quantitative index to evaluate the contractile function of local myocardium. Methods 24 healthy mongrel dogs were anesthetized and thoracotomy was performed. The proximal left anterior descending coronary artery was ligated. Myocardial tissue velocity images of three intact cardiac cycles before and after myocardial infarction were collected. The changes of myocardial strain rate curve in the long axis of each segment of left ventricular during systole were analyzed offline by digital ultrasound workstation. Results The peak value of systolic strain rate in affected segments after myocardial infarction was significantly lower than that of corresponding segments before infarction (P <0.05). Conclusion Strain rate can be sensitive, intuitive and noninvasive quantitative evaluation of regional myocardial contractility abnormalities may provide more early myocardial ischemia or infarction diagnostic information objective.