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目的观察健康比格犬左心室心肌三维峰值位移(3D-D)、位移达峰时间(3D-DTC)以及位移同步化指数(3D-DTSD)变化,量化评价左心室基础状态与急性心肌缺血状态心肌力学状态特征。方法建10只健康比格犬开胸模型,结扎左冠状动脉左前降支,诱导产生急性心肌缺血,分别采集基础状态和急性缺血状态每一状态下一个完整心动周期的全容积实时灰阶图像。应用斑点跟踪成像技术测量左心室心肌基础状态和急性缺血状态3D-D、3D-DTC,并计算出3D-DTSD,分析心肌基础状态和急性缺血状态3D-D的时序分布规律。结果 (1)急性心肌缺血状态与基础状态比较左心室各节段心肌3D-D均呈下降趋势,其中急性心肌缺血状态左心室心肌底前间隔、中前间隔、中间隔、尖前壁、尖间隔3D-D分别为(2.464±0.624)、(2.526±1.205)、(2.770±1.082)、(1.627±0.935)、(1.866±1.150)mm,基础状态的以上部位3D-D分别为(3.722±1.280)、(4.176±1.567)、(4.127±1.429)、(2.897±1.062)、(3.413±1.565)mm,两者比较差异有统计学意义(t=2.785、2.815、2.320、3.542、2.997,P均<0.05)。(2)急性心肌缺血状态底前壁、底前间隔、底间隔、底下壁、底后壁、底侧壁、中前壁、中前间隔、中间隔、中下壁、中后壁、中侧壁、尖前壁、尖间隔、尖下壁、尖侧壁3D-DTC分别为(325.43±78.26)、(339.21±65.81)、(347.59±86.21)、(304.27±112.34)、(296.58±114.52)、(306.18±57.17)、(342.82±79.68)、(351.63±84.21)、(332.55±171.15)、(336.66±169.53)、(304.09±87.56)、(329.07±107.62)、(435.25±66.99)、(400.48±149.48)、(375.92±190.36)、(352.46±86.38)ms,基础状态的以上部位3D-DTC分别为(228.00±64.50)、(194.49±50.81)、(193.50±72.52)、(235.26±74.76)、(213.98±85.46)、(221.38±70.44)、(233.78±69.31)、(224.19±10.40)、(193.95±66.42)、(214.17±60.66)、(220.90±61.83)、(253.59±65.13)、(246.71±79.47)、(240.38±60.66)、(248.56±47.58)、(253.93±73.59)ms,急性缺血状态与基础状态比较左心室各节段心肌3D-DTC均发生明显延迟,除底下壁、中下壁、尖下壁和中侧壁外,余节段差异有统计学意义(t=4.601、4.517、6.516、2.620、2.857、2.868、4.745、2.708、2.652、7.469、3.345、3.004,P均<0.05)。(3)急性心肌缺血状态与基础状态比较左心室心肌3D-DTSD增大,差异有统计学意义(68.29±22.18,50.28±20.30,t=2.582,P<0.05)。结论实时三维峰值位移作为终点力学参数能够敏感地反映急性心肌缺血状态左心室异常的结构和力学状态,有助于深入揭示急性心肌缺血后左心室的运动状态。
Objective To observe the 3D-D, 3D-DTC and 3D-DTSD of left ventricular myocardium in beagle dogs, and to quantitatively evaluate the changes of left ventricular basic state and acute myocardial ischemia Status of Cardiac Mechanics State Characteristics. Methods Ten healthy Beagle dogs were thoracotomized. Ligation of the left anterior descending branch of the left coronary artery was performed to induce acute myocardial ischemia. Whole-volume real-time grayscales of one intact cardiac cycle in each state of basal state and acute ischemic state were collected. image. 3D-D and 3D-DTC were measured by speckle tracking imaging. The 3D-DTSD was calculated and the distribution of 3D-D in myocardial basal state and acute ischemic state was analyzed. Results (1) Compared with basal state, the myocardial 3D-D in all segments of left ventricle showed a decreasing trend. The anterior myocardial ventricular septum, anterior septum, septum, apical anterior wall , And 3D-D at the apical intervals were (2.464 ± 0.624), (2.526 ± 1.205), (2.770 ± 1.082), (1.627 ± 0.935) and (1.866 ± 1.150) mm respectively. The 3D- 3.722 ± 1.280), (4.176 ± 1.567), (4.127 ± 1.429), (2.897 ± 1.062) and (3.413 ± 1.565) mm respectively, with significant difference between the two groups (t = 2.785,2.815,2.320,3.542,2.997 , P <0.05). (2) acute myocardial ischemia, the anterior wall, anterior septum, septal bottom, bottom wall, bottom posterior wall, bottom side wall, anterior wall, anterior septum, septum, middle and lower wall, in the posterior wall, in The 3D-DTC of side wall, apical anterior wall, apical septum, inferior apical wall and apical wall were (325.43 ± 78.26), (339.21 ± 65.81), (347.59 ± 86.21), (304.27 ± 112.34), (296.58 ± 114.52 , (306.18 ± 57.17), (342.82 ± 79.68), (351.63 ± 84.21), (332.55 ± 171.15), (336.66 ± 169.53), (304.09 ± 87.56), (329.07 ± 107.62), (435.25 ± 66.99) (400.48 ± 149.48), (375.92 ± 190.36) and (352.46 ± 86.38) ms respectively. The 3D-DTC values of the above sites were (228.00 ± 64.50), (194.49 ± 50.81), (193.50 ± 72.52) and (235.26 ± (213.98 ± 85.46), (221.38 ± 70.44), (233.78 ± 69.31), (224.19 ± 10.40), (193.95 ± 66.42), (214.17 ± 60.66), (220.90 ± 61.83), (253.59 ± 65.13) , (246.71 ± 79.47), (240.38 ± 60.66), (248.56 ± 47.58) and (253.93 ± 73.59) ms respectively. Compared with the basal state, 3D-DTC in all segments of the left ventricle was significantly delayed. Wall, middle and lower wall, pointed lower wall and medial side Statistically significant, the differences in the segment I (t = 4.601,4.517,6.516,2.620,2.857,2.868,4.745,2.708,2.652,7.469,3.345,3.004, P <0.05). (3) Comparison of acute myocardial ischemia and basal state 3D-DTSD of left ventricular myocardium increased, the difference was statistically significant (68.29 ± 22.18, 50.28 ± 20.30, t = 2.582, P <0.05). Conclusion The real-time three-dimensional peak displacement as the end-point mechanical parameter can sensitively reflect the structure and mechanical state of left ventricular anomalies in acute myocardial ischemia and help to reveal the left ventricular motion after acute myocardial ischemia.