Mapping of regional myocardial strain and work during ventricular pacing: Experimental study using magnetic resonance imaging tagging
Mapping of regional myocardial strain and work during ventricular pacing: Experimental study using magnetic resonance imaging tagging
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DOI：
10.1016/s0735-1097(99)00068-6
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发表时间：
1999-05-01
影响因子：
24
通讯作者：
McVeigh, ER
中科院分区：
文献类型：
--
作者：
Prinzen, FW;Hunter, WC;McVeigh, ER
本研究的目的是确定心室起搏过程中左心室（LV）壁内心肌功能（肌纤维缩短和工作）的空间分布。背景心室起搏引起的异步电激活导致LV功能、灌注和结构的各种异常。这些紊乱可能是由区域收缩模式的异常引起的。然而，洞察这些模式在起搏期间是尚未limited.METHODS在七只麻醉犬，高空间和时间分辨率磁共振标记的图像采集在三个正交平面。三维变形数据和左心室腔压力和体积被用来确定中壁周向应变和外部和总的机械功在192个网站周围的左ventricular. Results心室起搏，收缩期纤维应变和外部工作的区域接近零起搏网站，并逐渐增加到正常值的两倍以上，在最偏远的地区。右心房起搏期间的总机械功标准化为38 +/- 13%（右心室心尖部[RVapex]起搏）和61 +/- 23%（左心室基底部[LVbase]起搏），靠近起搏部位分别为125 +/- 48%和171 +/- 60%（RVapex和LVbase起搏之间p < 0.05）。RVapex起搏期间做功减少的区域数量显著大于LVbase起搏期间。这与RVapex paced.CONCLUSIONS心室起搏导致左心室壁内肌纤维工作的三倍差异的全球左心室泵功能的减少。这种差异似乎大到足以将局部心肌功能视为异步电激活期间灌注、代谢、结构和泵功能异常的重要决定因素。在引起更多同步激动的部位起搏可能会限制这种紊乱的发生。(C)1999年由美国心脏病学会。
OBJECTIVES The purpose of this study was to determine the spatial distribution of myocardial function (myofiber shortening and work) within the left ventricular (LV) wall during ventricular pacing.BACKGROUND Asynchronous electrical activation, as induced by ventricular pacing, causes various abnormalities in LV function, perfusion and structure. These derangements may be caused by abnormalities in regional contraction patterns. However, insight into these patterns during pacing is as yet limited.METHODS In seven anesthetized dogs, high spatial and temporal resolution magnetic resonance-tagged images were acquired in three orthogonal planes. Three-dimensional deformation data and LV cavity pressure and volume were used to determine midwall circumferential strain and external and total mechanical work at 192 sites around the left ventricle.RESULTS During ventricular pacing, systolic fiber strain and external work were approximately zero in regions near the pacing site, and gradually increased to more than twice the normal value in the most remote regions. Total mechanical work, normalized to the value during right atrial pacing, was 38 +/- 13% (right ventricular apex [RVapex] pacing) and 61 +/- 23% (left ventricular base [LVbase] pacing) close to the pacing site, and 125 +/- 48% and 171 +/- 60% in remote regions, respectively (p < 0.05 between RVapex and LVbase pacing). The number of regions with reduced work was significantly larger during RVapex than during LVbase pacing. This was associated with a reduction of global LV pump function during RVapex pacing.CONCLUSIONS Ventricular pacing causes a threefold difference in myofiber work within the LV wall. This difference appears large enough to regard local myocardial function as an important determinant for abnormalities in perfusion, metabolism, structure and pump function during asynchronous electrical activation. Pacing at sites that cause more synchronous activation may limit the occurrence of such derangements. (C) 1999 by the American College of Cardiology.