Effects of ischemia on left ventricular apex rotation. An experimental study in anesthetized dogs.
Effects of ischemia on left ventricular apex rotation. An experimental study in anesthetized dogs.
复制标题
缺血对左心室心尖旋转的影响。
DOI：
10.1161/01.cir.92.12.3539
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发表时间：
1995
期刊：
影响因子：
37.8
通讯作者：
R. Beyar
中科院分区：
文献类型：
--
作者：
C. Kroeker;J. Tyberg;R. Beyar
背景
左心室（LV）扭转被定义为心脏收缩期间心室心尖相对于基底的逆时针旋转。我们最近发现，由于底部旋转是最小的，心尖旋转的测量反映了左心室扭转的动力学。由于已知缺血会影响心内膜和心外膜纤维力和缩短，因此会影响扭转力矩的跨壁平衡，因此我们假设缺血对等容舒张（IVR）期间的心尖旋转幅度和解旋有显著影响。
方法和结果
在16只开胸犬的左心室心尖部，用光学装置，同时记录心尖部旋转与左心室压力、心电图、左心室段长度和短轴直径。缺血是由左前降支（LAD）或回旋支（LCx）动脉的1- 2分钟圈套器闭塞引起的。LAD缺血对心尖旋转有明显影响：缺血10秒时心尖旋转幅度增加归因于内膜下功能障碍;最大心尖旋转发生在缺血10秒后。（在IVR期间）在整个缺血;一个矛盾的松弛模式的初始解扭，然后扭转和解扭在IVR期间与缺血;以及心尖旋转幅度随缺血而降低，这可能是由于透壁功能障碍。LCx闭塞对心尖旋转有类似的影响，除了在闭塞10秒时心尖旋转幅度没有增加，并且心尖旋转幅度没有随着严重缺血而降低。在控制缺血前条件下，在射血过程中观察到心尖旋转和节段长度之间的线性关系，而在IVR过程中观察到不同的、更陡峭的关系。对于局部缺血的节段，这种关系对于射血和IVR都变得非线性。
结论
LAD和LCx缺血对心尖旋转的动力学有深远的影响。缺血时出现反常的舒张模式。我们认为这些观察结果是由于扭转力矩的动态透壁平衡的变化，决定了左心室扭转。
BACKGROUND
Left ventricular (LV) twist has been defined as the counterclockwise rotation of the ventricular apex with respect to the base during systole. We recently showed that, since base rotation is minimal, measurement of apex rotation reflects the dynamics of LV twist. Since ischemia is known to affect endocardial and epicardial fiber force and shortening and therefore the transmural balance of torsional moments, we hypothesized that ischemia has a significant effect on apex-rotation amplitude and on untwisting during the isovolumic relaxation (IVR) period.
METHODS AND RESULTS
With an optical device coupled to the LV apex, apex rotation was recorded simultaneously with LV pressure, ECG, LV segment length, and minor-axis diameters in 16 open-chest dogs. Ischemia was caused by a 1- to 2-minute snare occlusion of either the left anterior descending (LAD) or circumflex (LCx) arteries. LAD ischemia had a pronounced effect on apex rotation: an increase in apex-rotation amplitude attributed to subendocardial dysfunction at 10 seconds of ischemia; maximum apex rotation occurring later (during the IVR period) throughout the ischemia; a paradoxical relaxation pattern of initial untwisting followed by twisting and untwisting during the IVR period with ischemia; and a decrease in the amplitude of apex rotation with ischemia, possibly due to transmural dysfunction. LCx occlusion had similar effects on apex rotation, except that apex-rotation amplitude was not increased at 10 seconds of occlusion and the amplitude of apex rotation did not decrease with severe ischemia. Under control preischemic conditions, a linear relationship between apex rotation and segment length was observed during ejection and a different, steeper relationship during IVR. With regionally ischemic segments, this relationship became nonlinear for both ejection and IVR.
CONCLUSIONS
Both LAD and LCx ischemia had profound effects on the dynamics of apex rotation. A paradoxical relaxation pattern occurred with ischemia. We suggest that these observations are due to changes in the dynamic transmural balance of torsional moments that determine LV twist.
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影响因子：
37.8
作者：
MOON, MR;INGELS, NB;MILLER, DC
通讯作者：
MILLER, DC
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