Effects of acute atrial dilation on heterogeneity in conduction in the isolated rabbit heart
Effects of acute atrial dilation on heterogeneity in conduction in the isolated rabbit heart
复制标题
DOI：
10.1046/j.1540-8167.2003.02280.x
复制
发表时间：
2003-03-01
影响因子：
2.7
通讯作者：
Allessie, MA
中科院分区：
文献类型：
--
作者：
Eijsbouts, SCM;Majidi, M;Allessie, MA
心房扩张和传导中的异质性。前言：心房扩张在房颤（AF）的发生和持续中起着重要作用。心房扩张增加的脆弱性AF的机制还没有完全understood.Methods和Results：在11只离体兔心脏，右心房急性扩张，增加心房内压从2至9和14厘米水柱。将240个电极的矩形标测阵列（空间分辨率0.5 mm）定位在右心房的游离壁上。从四个不同部位以240和125 msec的间隔起搏心房。在正常心房压力（2 cm 1120）下，各向异性比在1.5和1.7之间，在所有方向上传导均匀。将压力增加到9 cm H2O使快速起搏期间的标准化传导速度降低18%。传导缓慢和传导阻滞区域的发生率从6.6%和1.6%增加到10.2%和3.3%。在14 cm水柱时，传导速度下降31%，慢传导和阻滞的比例进一步增加至11.5%和6.6%（P < 0.001）。心房内传导阻滞线的出现在很大程度上取决于起搏部位。然而，在终嵴的头部起搏时，传导延迟没有增加，从右心房下部起搏时，发现了平行于主小梁和终嵴的几条传导阻滞线。在另外一系列的6个心脏中，也标测了左心房。左心房的扩张效果与右心房相当。心房压力增加到14 cm H2O增加了3倍至4倍的房内传导阻滞的数量。结论：急性心房扩张导致传导减慢和房内传导阻滞的数量增加。传导空间异质性的增加与心房壁的各向异性有关。
Atrial Dilation and Heterogeneity in Conduction. Introduction: Atrial dilation plays an important role in the development and persistence of atrial fibrillation (AF). The mechanisms by which atrial dilation increases the vulnerability to AF are not fully understood.Methods and Results: In 11 isolated rabbit hearts, the right atrium was acutely dilated by increasing the intra-atrial pressure from 2 to 9 and 14 cm H2O. A rectangular mapping array of 240 electrodes (spatial resolution 0.5 mm) was positioned on the free wall of the right atrium. The atrium was paced from four different sites at intervals of 240 and 125 msec. At normal atrial pressure (2 cm 1120), conduction was uniform in all directions with an anisotropy ratio between 1.5 and 1.7. Increasing the pressure to 9 cm H2O decreased the normalized conduction velocity during rapid pacing by 18%. The incidence of areas of slow conduction and conduction block increased from 6.6% and 1.6% to 10.2% and 3.3%. At 14 cm H2O, conduction velocity decreased by 31% and the percentage of slow conduction and block further increased to 11.5% and 6.6% (P < 0.001). The appearance of lines of intra-atrial block was largely dependent on the pacing site. Whereas during pacing at the cranial part of the crista terminalis no increase in conduction delays occurred, pacing from the low right atrium unmasked several lines of block oriented parallel to the major trabeculae and the crista terminalis. In an additional series of six hearts the left atrium also was mapped. The effect of dilation of the left atrium was comparable to that of the right atrium. Increasing the atrial pressure to 14 cm H2O increased the amount of intra-atrial conduction block threefold to fourfold.Conclusion: Acute atrial dilation results in slowing of conduction and an increase of the amount of intra-atrial conduction block. The increase in spatial heterogeneity in conduction was related to the anisotropic properties of the atrial wall.