心房神经节消融后心房结构重构与心房颤动诱发的关系

目的研究心房心外膜神经节丛（GP）消融后心房基质的变化，探讨其与心房颤动（房颤）诱发的关系。方法10只犬随机分为假手术组和GP消融组。所有犬均行超声心动图后无菌下右侧开胸，观察右心房短阵快速电刺激诱发房颤情况。之后GP消融组分别消融心房右前和右下GP，消融后即刻观察右心房短阵快速电刺激诱发房颤情况。所有犬喂养8周后，同样方法再观察房颤诱发情况。取出心脏分离左、右心房肌组织，采用放射免疫法检测脑钠肽（BNP）水平及免疫组化法检测神经密度；同样方法检测犬开胸前和开胸后8周血浆BNP水平和超声心动图。结果假手术组和GP消融后即刻右心房刺激未能诱发出房颤，但房颤在GP消融后8周易诱发；血浆和右心房组织BNP水平在GP消融后8周明显升高（119．5±22．6）pg／mlV8（167．7±26．4）pg／ml，（213．2±34．9）pg／gVS（287．6±36．4）pg／g，P〈0．05]，但左心房BNP水平无明显变化；两组犬术前和术后左右心房大小均无明显变化；GP消融8周后右心房GAP43、TH和ChAT阳性纤维的密度低于假手术组，差异有统计学意义（791±714）permm2vs（2540±863）permm2，（448±582）permm。VS（1855±623）permm2，（580±726）permm2vs（2833±851）permm2，P〈0．05]，但左心房无明显变化。结论心房心外膜GP消融后，心房基质发生重构，可能是GP消融后房颤易诱发的原因。

Relationship between atrial structural remodeling and inducibility of atrial fibrillation after epicardial ganglionic plexi ablation

Objective To investigate the atrial substrate changes after ganglionated plexi (GP) ablation and the relationship between atrial structural remodeling and inducibility of atrial fibrillation (AF). Methods Ten dogs were randomly divided into sham-operated group and GP ablation group. All animals un-derwent a right thoracotomy at the 4th intercostal space. Induced AF was measured by burst rapid pacing at right atrium. After anterior right GP and inferior right GP ablation,AF was measured again in the GP ablation group. The chest was closed and the animals were allowed to recover for 8 weeks. AF was tested again after 8 weeks. Atrial natriuretic peptide (BNP) in blood and atrial tissues was examined by radioimmunoassay. Immu-nocytochemical staining of cardiac nerves was performed. Results AF was not induced after instant GP abla-tion by burst rapid pacing and easily induced after 8 weeks while AF was not observed in the sham-operated group. Compared with sham-operate group,the blood BNP and right atrium BNP were increased significantly 8 weeks after GP ablation (119.5±22.6) vs (167.7±26.4) pg/ml,(213.2±34.9) vs (287.6±36.4) pg/g,P <0.05]. However,the BNP in left atrium did not change and there was no significant change in the a-trium size before and after GP ablation. In GP ablation group, the density of GAP43-pesitive, TH-positive and ChAT-positive nerves in the right atrium was lower than that in sham-operated tissues (791±714 vs 2540±863,448±582 vs 1855±623 and 580±726 vs. 2833±851 per mm2, P < 0.01, respectively). Conclusion Atrial remodeling after GP ablation may be one of the mechanisms of induced AF.