中文摘要：

为负责的客观位于 atrial tachyarrhythmias 的 cardioversion 下面机制电、机械在中庭以后改变可能是类似的，但是他们仍然不完全地被理解，并且在短期的快速的 atrial 激活是这改变的基础以后，在 atrial 心肌层的变化是否组织，是未知的。我们试图调查机械功能和 atrial ultrastructural 在短期的快速的 atrial 激活，和可能的关系在之间前后改变的 atrial 以免可收缩、解剖的 atrial 改变。十七条 anesthetized 杂种狗被划分成的方法试验性(n=12 ) 并且控制(n=5 ) 组。试验性的组在正确 atrial 附器经历了一根 transvenous 皮带的插入并且在 450bpm 踱步的 atrial 5 小时。有效倔强的时期(ERP ) 和 P 波浪持续时间在 5 小时的踱步前后被测量。左 atrial 波形的声学的 quantification (AQ ) 在 5 小时的踱步前后被记录。所有大小在湾穴节奏被做。狗被打死，在左 atrial trabeculae 和附器的心肌层被光和电子显微镜学检验。控制狗没经历踱步，但是考试在试验性的组的相应于那的时间被执行。尽管有在在在试验性的组，踱步的 5 小时的快速的 atrial 以后的心率和左室的压力的变化的缺席的结果离开了水库和水管功能没改变的 atrial，而增加的 atrial 尺寸和 atrial 增强软件功能减少了。标记变化在细胞的基础被看见，例如在 mitochondrial 形状和尺寸的 myofibrils，肝糖的累积，和变化的损失。没有变化在控制组被发现。结论短期的快速的 atrial 激活能引起改变的 electrophysi-ological 和可收缩、解剖的左 atrial 改变，并且解剖改变可以贡献电、可收缩的 atrial 的发展改变。

英文摘要：

Objective The underlying mechanisms responsible for both electrical and mechanical remodeling of the atrium after cardioversion of atrial tachyarrhythmias may be similar, but they are still incompletely understood, and whether the changes in atrial myocardium structure after short-term rapid atrial activation is the basis for this remodeling is unknown. We aimed to investigate atrial mechanical function and atrial ultrastructural change before and after short-term rapid atrial activation, and the possible relation between lest atrial contractile and anatomical remodeling. Methods Seventeen anesthetized mongrel dogs were divided into experimental （n=12） and control （n=5） groups. The experimental group underwent insertion of a transvenous lead at the right atrial appendage and 5-hour of atrial pacing at 450bpm. Effective refractory period （ERP） and P-wave duration were measured before and after 5-hour pacing. Acoustic quantification （AQ） of left atrial waveforms was recorded before and after 5-hour pacing. All measurements were made in sinus rhythm. Dogs were killed and the myocardium in left atrial trabeculae and appendages was examined by light and electron microscopy. Control dogs did not undergo pacing, but the examinations were performed at the times corresponding to that for the experimental group. Results Despite the absence of changes in heart rate and left ventricular pressure after 5-hour rapid atrial pacing in the experimental group, left atrial reservoir and conduit function did not change, whereas atrial size increased and atrial booster function decreased. Marked changes were seen in cellular substructures, such as loss ofmyofibrils, accumulation of glycogen, and changes in mitochondrial shape and size. No changes were found in the control group. Conclusions Short-term rapid atrial activation can cause electrophysi- ological remodeling and left atrial contractile and anatomical remodeling, and anatomical remodeling may contribute to the development of atrial electrical and contractile