TORSION OF THE LEFT-VENTRICLE DURING THE EJECTION PHASE IN THE INTACT DOG
TORSION OF THE LEFT-VENTRICLE DURING THE EJECTION PHASE IN THE INTACT DOG
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DOI：
10.1093/cvr/18.3.183
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发表时间：
1984-01-01
影响因子：
10.8
通讯作者：
CORDAY, E
中科院分区：
文献类型：
--
作者：
ARTS, T;MEERBAUM, S;CORDAY, E
左心室（LV）的扭转与心尖相对于基底绕LV长轴的旋转有关。在9只麻醉闭胸犬上，用二维超声心动图评价了左心室力学的数学模型，该模型将扭转与纤维缩短的跨壁分布联系起来。扭转计算为在二尖瓣和低乳头水平获得的LV的回声衍生横截面投影的旋转角度（弧度）之间的差值，除以在长轴横截面中测量的这些投影之间的轴向距离，再乘以LV的中间乳头横截面投影的外径。缩短扭转比（STR）被定义为在弹射过程中发生的内壁缩短与扭转的比率。在一系列的11次测量中，每次测量都基于15个心动周期的帧到帧分析，发现STR为2.31 ±。0.23 rad-1 [弧度]（平均值。+-。SD），而数学模型预测在宽范围的前负荷、后负荷和收缩性水平上的STR值为2.4 rad-1。二维超声心动图明显验证了左心室力学模型预测的正常犬左心室扭转的存在。
Torsion of the left ventricle (LV) is associated with rotation of the apex with respect to the base around the long axis of the LV. A mathematical model of LV mechanics, which relates torsion to transmural distribution of fiber shortening, was evaluated with 2-dimensional echocardiography in 9 anesthetized closed-chest dogs. Torsion was calculated as the difference between the angles of rotation (radians) of echo-derived transverse cross-section projections of the LV obtained at the mitral valve and low papillary level, divided by the axial distance between these projections measured in a long-axis cross-section, and multiplied by the outer radius in a mid-papillary transverse projection of the LV. A shortening to torsion ratio (STR) was defined as the ratio of inner wall shortening to torsion occurring during ejection. In a series of 11 measurements, each based on frame-to-frame analysis of 15 cardiac cycles, STR was found to be 2.31 .+-. 0.23 rad-1 [radian] (mean .+-. SD), whereas the mathematical model predicted a STR value of 2.4 rad-1 over a wide range of preload, afterload and contractility levels. Two-dimensional echocardiography apparently validates the presence of torsion in the normal canine left ventricle, as predicted by the model of left ventricular mechanics.