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目的:应用组织速度成像(TVI)技术研究犬左室急性心肌缺血状态下右心功能的变化特点及其相互关系。方法:10只犬行右冠状动脉前降支结扎,制作急性心肌缺血模型,分别于冠状动脉左前降支结扎前、后10min采集心尖四腔切面图像,测量缺血前后右室壁、右房壁及三尖瓣环的收缩期峰值速度(Vs)、舒张早期峰值速度(Ve)、舒张晚期峰值速度(Va)、右室射血分数(RVEF),用导管法测肺动脉收缩压(PASP)。结果:与缺血前比较,左室局部急性心肌缺血后PASP增加(P<0.05),RVEF降低(P<0.05),右室壁和三尖瓣环的Vs、Ve及Va降低(P<0.05),右房壁Vs和Va增加(P<0.05)。心肌缺血前,右室壁与右房壁的运动速度无明显相关性;心肌缺血后两者呈负相关,RVEF与右室壁及三尖瓣环的Vs均呈正相关,PASP与RVEF呈负相关。结论:急性心肌缺血可引起右室壁运动功能减退,右房壁运动功能代偿性增加。
OBJECTIVE: To study the changes of right ventricular function in dogs with acute left ventricular myocardial ischemia using tissue velocity imaging (TVI) technique and its correlation. Methods: A total of 10 dogs underwent right anterior descending coronary artery ligation to establish an acute myocardial ischemia model. Coronary four-chamber images were collected 10 min before and after the left anterior descending coronary artery was ligated. The right and left atrium The systolic peak velocity (Vs), early diastolic peak velocity (Ve), late diastolic peak velocity (Va), right ventricular ejection fraction (RVEF) and pulmonary artery systolic pressure (PASP) . Results: Compared with those before ischemia, PASP increased (P <0.05), RVEF decreased (P <0.05) and Vs, Ve and Va decreased in right ventricular wall and tricuspid annulus (P < 0.05). Vs and Va in the right atrium increased (P <0.05). Right ventricular wall and right atrial wall velocity had no significant correlation before myocardial ischemia. There was a negative correlation between myocardial ischemia and RVEF, Vs of right ventricular wall and tricuspid annulus, PASP and RVEF Negative correlation. Conclusion: Acute myocardial ischemia can cause hypofunction of right ventricular wall and compensatory increase of right atrial wall.