中文摘要：

目的通过分析迷走神经调节的心房电生理指标（心房有效不应期及心房颤动易感窗口）的变化，间接揭示上腔静脉（SVC）隔离对犬的心房迷走神经功能及心房颤动（房颤）易感性的影响。方法9条成年杂种犬，全身麻醉下行颈交感-迷走神经干剥离术。经右颈内静脉穿刺放置冠状静脉窦导管，经股静脉穿刺放置右心室导管（行临时右心室起搏）、环状标测导管（Lasso导管）及消融导管。静脉应用美托洛尔阻断交感神经活性。分别于SVC隔离前后在基础状态及迷走神经刺激时测量右心耳（RAA）、冠状静脉窦近端（CSp）和冠状静脉窦远端（CSd）的不应期（ERP）、心房易感窗口（VW）及窦性周长（SCL）。结果（1）窦性周长的变化SVC隔离前迷走神经刺激明显缩短SCL[（65．78±28．49）次／min vs（142．67±15．42）次／min，P〈0．001]，SVC隔离后基础状态及迷走神经刺激下SCL差异无统计学意义[（134．89±19．19）次／minVS（114．33±31．41）次／min，P〉0．05]。（2）有效不应期的变化SVC隔离前，迷走神经刺激下测得的心房ERP较基础状态下明显缩短[右心耳（RAA）分别为（51．11±18．33）ms vs（101．11±27．59）ms；CSd分别为（56．67±22．36）ms vs（98．89±14．53）ms；CSp分别为（48．89±25．22）ms vs（101．11±12．69）ms，P〈0．001]。SVC隔离后，迷走神经刺激所致的心房ERP缩短的能力明显下降[RAA分别为（94．40±16．70）msVS（94．44±16．67）ms；CSd分别为（89±15）msVS（96．7±18．0）ms；CSp分别为（93．3±18．7）msvs（98．9±20．3）ms，P〉0．05]。（3）心房易感窗口的变化SVC隔离前后基础状态下测得的Vw无变化。SVC隔离后迷走神经刺激时测得的Vw较隔离前明显降低[RAA分别为（6．67±11．18）msvs（21．11±20．88）ms，CSd分别为（8．89±14．52）ms vs（16．66±23．97）ms，CSp分别为（2．22±6．67）

英文摘要：

Objective This study hypothesized that superior vena cava（ SVC ）isolation could result in vagal denervation to atria. Methods Nine adult mongrel dogs under general anesthesia were involved in this study. Bilateral cervical sympathovagal trunks were decentralized. Metoprolol was given to block sympathetic effects. Muhipolar catheters were placed into right atrial appendage （ RAA ）, coronary sinus （ CS ） and right ventricle （RV） through right internal jugular vein and left femoral vein, respectively. SVC isolation was performed guided by mapping catheter（Lasso） placed at the junction of SVC and right atrium through right femoral vein. Complete atrioventricular block was achieved by His bundle ablation and RV pacing was applied through RV catheter. Atrial effective refractory period （ ERP）, vulnerability window （ VW ） of AF, and sinus cycle length （SCL） were measured at RAA,distal CS （CSd） and proximal CS （CSp） at baseline （without vagal stimulation） and vagal stimulation before and after SVC isolation. Results SCL decreased significantly during vagal stimulation before SVC isolation [ （ 65.78 ± 28.49 ）/min vs （ 142.67 ± 15.42 ）/min, P 〈 0. 0013 , while SCL remained unchanged during vagal stimulation after SVC isolation[ （ 134. 89 ± 19. 19）/min vs （ 114. 33 ± 31.41 ）/min,P 〉0. 053. ERP during vagal stimulation decreased significantly before SVC isolation compared with that at baseline[ （51.11 ± 18.33）ms vs （101.11 ±27.59）ms at RAA; （56. 67 ±22.36）ms vs （98.89 ± 14. 53 ）ms at CSd; （48. 89 ± 25.22 ）ms vs （ 101.11 ± 12. 69 ）ms at CSp,P 〈 0. 001 ], while E RP remained un- changed during vagal stimulation after SVC isolation compared with that at baseline [ （ 94.40 ± 16. 70 ） ms vs （94. 44 ± 16. 67）ms at RAA; （89 ± 15） vs （96. 7 ± 18. 0）ms at CSd; （93.3 ± 18. 7）ms vs （98. 9 ±20. 3） ms at CSp, P 〉 0. 053. The shortening of ERP after SCV isolation decreased significantly compared with that bef