中文摘要：

目的研究迷走神经干预对心房电重构的影响。方法24只杂种犬随机分为3组，为排除交感神经对心房电重构的影响，3组犬均应用美托洛尔阻断交感神经效应。A组10只犬快速心房起搏过程中无迷走神经干预，B组8只犬应用阿托品阻断迷走神经效应，C组6只犬在快速心房起搏过程中同时进行迷走神经刺激。在右心房（RA）、冠状静脉窦（CS）和右心室（RV）放置多极导管。通过RA电极导管进行600次／min心房起搏30min构建急性心房电重构模型。在右心房快速起搏前后测量基础状态（无迷走神经刺激）和迷走神经刺激下的心房有效不应期（AERP）和心房颤动（房颤）易感窗口（VW）。结果A组犬右心房快速起搏后基础状态下及迷走神经刺激时的AERP较起搏前明显缩短（P〈0．05）。B组犬右心房快速起搏后基础状态下及迷走神经刺激时的AERP较起搏前无明显变化（P〉0．05）。C组犬右心房快速起搏后基础状态下及迷走神经刺激时的AERP较起搏前明显缩短（P〈0．05）。A组及C组右心房快速起搏后AERP缩短值明显大于B组（P〈0．05），但A组及C组AERP缩短值差异无统计学意义（P〉0．05）。迷走神经刺激下，B组犬在右心房快速起搏前后均较难诱发房颤（VW接近0），A组及C组犬右心房快速起搏后较起搏前容易诱发房颤（P〈0．05）。结论短期右心房快速起搏导致的心房电重构过程中伴随着迷走神经兴奋性增强。迷走神经兴奋性增强及迷走神经刺激加重心房电重构，导致房颤易感性增加。迷走神经阻滞能减轻心房电重构，降低房颤易感性。

英文摘要：

Objective To investigate the impact of vagal activity on atrial electrical remodeling（AER） in dogs, Methods Twenty-four adult mongrel dogs under general anesthesia were randomized into 3 groups. Sympathetic activity was blocked by administration of metoprolol in 3 groups. AER was performed by 600 bpm pacing through high right atrium（RA） catheter for 30 minutes, The changes of vagal modulation to atria after RA pacing were observed in 10 dogs without vagal interruption in group A, The effects of vagal intervention on AER were investigated in 8 dogs with administration of atropine in group B. The impact of aggressively vagal activity on AER was studied in 6 dogs with bilateral cervical sympathovagal trunks stimulation during RA pacing in group C, Muhipolar catheters were placed into RA, coronary sinus （CS） and right ventricular（RV）. Atrial effective refractory period （AERP） and vulnerability window （VW） of atrial fibrillation were measured with and without vagal stimulation before and after RA pacing, Results In group A, AERP decreased significantly at baseline （ without vagal stimulation） and during vagal stimulation after RA pacing compared with that before RA pacing （ P 〈 0.05 ）. In group B, AERP remained unchanged at baseline and vagal stimulation after RA pacing compared with that before RA pacing（ P 〉 0. 05 ）. In group C, AERP shortened significantly at baseline and vagal stimulation after RA pacing compared with that before RA pacing （ P 〈0. 05 ）, AERP shortening after RA pacing in group A and C increased significantly than that in group B （ P 〈 0.05 ）. Atrial fibrillation could not be induced at baseline （VW close to 0） before and after RA pacing in three groups, VW became widen significantly during vagal stimulation after RA pacing compared with that before RA pacing in group A and C （ P 〈 0. 05 ） , while VW remained unchanged in group B （ VW close to 0）. Conclusions AER is accompanied by the increase of atrial vagal modulation. The increase