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目的研究迷走神经对心房电重构的影响。方法24只杂种犬随机分为3组,3组犬均应用美托洛尔阻断交感神经效应。A组(10只):心房电重构过程中无迷走神经干预:B组(8只):应用阿托品阻断迷走神经效应;C组(6只):在心房电重构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导管进行600次／min的起搏30 min构建急性心房电重构模型。在心房电重构前、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(ERP)和心房颤动易感窗口(VW)。结果A组犬心房电重构后基础状态下及迷走神经刺激时的ERP较心房电重构前明显缩短(P值均<0．05)。B组犬心房电重构后与心房电重构前基础状态下及迷走神经刺激时的ERP的差异无统计学意义(O值均>0．05)。C组犬心房电重构后基础状态下及迷走神经刺激时的ERP较心房电重构前明显缩短(P值均<0．05)。A组及C组心房电重构后ERP缩短值明显大于B组(P值均<0．05),但A组及C组ERP缩短值的差异无统计学意义(P>0．05)。基础状态下,3个实验组的实验犬在心房电重构前后均不能诱发心房颤动(VW接近0)。迷走神经刺激下, B组实验犬在心房电重构前后也不能诱发心房颤动(VW接近0),但A组及C组实验犬电重构后较电重构前容易诱发心房颤动(P值均<0．05)。结论短期的心房电重构能够缩短心房的有效不应期。心房电重构可能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可能加重心房电重构,导致心房颤动易感性增加。迷走神经阻滞能减轻心房电重构,降低心房颤动易感性。
Objective To study the effect of vagus nerve on atrial electrical remodeling. Methods 24 Mongolian dogs were randomly divided into 3 groups. Metoprolol was used to block the sympathetic effect in 3 dogs. Group A (n = 10): No vagal intervention during atrial electrical remodeling: group B (n = 8): atropine was used to block the vagal nerve; group C (n = 6): vagal stimulation was performed during atrial electrical remodeling. Multi-polar catheters were placed in the right atrium (RA), coronary sinus (CS) and right ventricle (RV). Acute atrial electrical remodeling models were established by RA catheterization at 600 beats / min for 30 min. Atrial electrical remodeling (ERP) and atrial fibrillation susceptibility window (VW) were measured before and after atrial electrical remodeling and basal state (no vagal stimulation) and vagus nerve stimulation. Results In group A, the ERP of basilar electrical remodeling and vagus nerve stimulation were significantly shortened before atrial electrical remodeling (P <0.05). There was no significant difference in ERP between basilar electrical remodeling and basilar electrical remodeling and vagus nerve stimulation in group B (all O values> 0.05). Compared with the atrial electrical remodeling, the ERP of basilar electrical remodeling and the vagus nerve stimulation in group C were significantly shortened (P <0.05). ERP shortening in group A and group C after atrial electrical remodeling was significantly greater than that in group B (all P <0.05), but there was no significant difference in ERP shortening between group A and group C (P> 0.05). Under basal conditions, experimental dogs in three experimental groups failed to induce atrial fibrillation (VW close to 0) before and after atrial electrical remodeling. Vagus nerve stimulation, group A dogs before and after atrial electrical remodeling can not induce atrial fibrillation (VW close to 0), but dogs in group A and group C electrical reconstitution before electrical reconstitution easily induce atrial fibrillation (P value <0.05). Conclusion Short-term atrial electrical remodeling can shorten the effective refractory period of the atria. Atrial electrical remodeling may be associated with increased excitability of the vagus nerve. Increased vagal excitement and vagus nerve stimulation may aggravate atrial electrical remodeling, leading to increased susceptibility to atrial fibrillation. Vagal block can reduce atrial electrical remodeling and reduce the susceptibility to atrial fibrillation.