自主神经对左上肺静脉电生理特征的影响

目的研究迷走神经刺激和心脏自主神经阻断对左上肺静脉(LSPV)电生理特征影响。方法用7只成年杂种犬自身对照,观察基础状态、左侧迷走神经干刺激、阻断迷走神经和阻断自主神经等不同状态下犬的心房和LSPV远端(LSPV-D)、中端(LSPV-M)、近端(LSPV-P)有效不应期(ERP)的变化,以及起搏肺静脉时心房颤动(简称房颤)诱发率的变化。结果①迷走神经刺激时LSPV的ERP均较基础状态下缩短,房颤的诱发率最高(71.4%)。②单用阿托品阻断迷走神经时LSPV-M的ERP较基础状态下延长(125.8±9.1msvs112.9±13.8ms,P<0.05),LSPV-P和LSPV-D无变化,但房颤诱发率较基础状态下和迷走神经刺激时下降(17.1%vs24.8%,71.4%,P<0.05)。③联合应用阿托品和普奈洛尔阻断自主神经时LSPV-D、LSPV-M和LSPV-P的ERP均显著延长,房颤的诱发率最低(7.6%)。④基础状态下LSPV-D的ERP长于LSPV-P(118.6±17.5msvs106.4±10.7ms,P<0.05),阻断自主神经时LSPV-D的ERP短于LSPV-P(135.0±8.2msvs151.4±12.1ms,P<0.05)。结论LSPV的电生理特征存在“异质性”,对阻断自主神经的药物反应性也不同,对房颤的发生和维持有重要作用。而自主神经张力的变化可以改变LSPV的电生理特性,其中交感神经也是主要原因之一。

Effects of autonomic nerves system on electrophysiological properties of left superior pulmonary veins

Objective To investigate effect of left vagal stimulation and autonomic nerve blockade on the electrophysiological properties of the left superior pulmonary veins (LSPV). Method In seven adult mongrel dogs, the effective refractory period (ERP) changed in the distal LSPV(LSPV-D), medial LSPV(LSPV-M) and proximal LSPV(LSPV-P) along with atrial fibrillation(AF) inducibility were studied in the baseline state, during left vagal trunk stimulating and in the present of autonomic blockade. Result The left vagal stimulating significantly decreased the ERP of LSPV and markedly enhanced the inducibility of AF(71.4%).②After intravenous atropine administration, significant change of ERP was observed only in LSPV-M(125.8±9.1 ms vs 112.9±13.8 ms, P<0.05),but not in LSPV-P or LSPV-D. The inducibility of AF was reduced(17.1%) compareing with the baseline state (24.8%)and during left vagus trunk stimulating(71.4%). ③ The ERP of pulmonary veins was increased significantly and the inducibility of AF was greatly suppressed by coadministration of atropine and propranolol (7.6%).④Under the baseline state the ERP of LSPV-D was longer than that of LSPV-P(118.6±17.5 ms vs 106.4±10.7 ms, P<0.05), but the ERP of LSPV-D was shorter than that of LSPV-P in presence of atropine and propranolol(135.0±8.2 ms vs 151.4±12.1 ms, P<0.05). Conclusions Electrophysiological properties and responses to autonomic blockade of LSPV present heterogeneity, which may play an important role in the maintenance of AF. These differential effects result from autonomic nerves system, particularly sympathetic nerves system.