不同电压刺激双侧迷走神经干及星状神经节对血压、心率及房颤诱发率的影响

Voltage dependent effect of cervical vagus trunk and stellate ganglion stimulation on arterial pressure,heart rate and atrial fibrillation inducibility

目的观察不同电压刺激犬颈部双侧迷走神经干及星状神经节对血压,心率及房颤诱发率的影响。方法成年杂种犬10只,全身麻醉,机械通气下钝性分离并暴露颈部双侧迷走神经干及星状神经节心支,分别将刺激电极插入神经,20Hz固定刺激频率下,分别给予不同强度电压行双侧颈部左右迷走神经干及星状神经节心支刺激。分别记录左右侧迷走及星状神经节刺激前后血压、心率及房颤诱发率。结果双侧迷走神经干刺激时随着刺激电压的增加(0~8V),收缩压和舒张压均逐渐降低,到2V时达到最大效应。心率逐渐减慢,到4V时达到最大效应。当给予左侧迷走神经神经干+高右房程序刺激时,分别采用S1S2及S1S2刺激方式的房颤诱发率分别为45.00%和13.33%(P<0.05)。右侧迷走神经干+高右房S1S2及S1S2程序刺激时,房颤的诱发率分别为80.00%和16.66%(P<0.05)。右侧迷走神经干刺激时所有的动物均表现窦性心动过缓,左侧迷走神经刺激时1/10的犬表现为Ⅰ度、Ⅱ度房室传导阻滞和窦性停搏,1/10的犬出现了自发心房颤动。刺激双侧星状神经节心支时,收缩压,舒张压及心率均随刺激电压的增加逐渐升高,左侧刺激引起收缩压升高的幅度明显高于右侧(P<0.05),与基础刺激相比星状神经节刺激可显著增加房颤的诱发率,S1S1程序刺激后的房颤诱发率明显高于S1S2刺激。右侧星状神经节刺激时的房颤诱发率明显高于左侧(P<0.05)。结论刺激双侧迷走神经干可引起犬血压降低、心率减慢。刺激双侧星状神经节均可引起犬血压、心率加快且右侧刺激对心率和血压的影响均较左侧更明显。

Objective To explore the voltage dependent effect of cervical vagus trunk and stellate ganglion stimulation on arterial pressure,heart rate and atrial fibrillation inducibility.Methods All animals were generally anesthetized and mechanically ventilated,the bilateral cervical vagus and sympathetic nerves cardiac branches from ten mongrel dogs were split and stimulated,the silver electrodes were inserted into the nerves.The blood pressure,heart rate and atrial fibrillation inducibility were determined in different stimulation intensity with the same frequency（20 Hz）.Results With the increase of the stimulation voltage（0-8 V）,both the systolic and diastolic pressure gradually decreased under the stimulation of bilateral vagus nerve,and the maximum effect reached to 2 V.The heart rate gradually slowed down and reached the maximum effect at 4 V.The rate of atrial fibrillation induced by left vagus nerve stimulation（VNS）plus high right atrial（HRA）S1 S1 and S1 S2 stimulation were 45%vs.13.3%respectively（P〈0.05）.The inducibility of atrial fibrillation induced by right VNS plus HRA S1 S1 and S1 S2 stimulation were 80% vs.16.66%respectively（P〈0.05）.On the left VNS,1/10 of the dogs showed I,II AV block and sinus arrest,1/10 dogs had spontaneous atrial fibrillation,and all animals exhibited sinus bradycardia by the right VNS.When stimulated the bilateral stellate ganglion（SG）cardiac branches,with the increase of stimulating voltage（0-22 v）,systolic blood pressure and diastolic blood pressure and heart rate were increased gradually,elevated systolic blood pressure caused by left SG was significantly higher than that of right SG（P〈0.05）;compared with the baseline,SG stimulation can induce significant increase in the rate of atrial fibrillation,and atrial fibrillation inducibility by S1 S1 stimulation was higher than that of S1 S2 stimulation.The rate of atrial fibrillation induced by the right SG was significantly higher than that induced by the left SG（P〈0.05）.Conclusion Stimulation of bilateral vagus nerve trunk can cause the decrease of blood pressure and heart rate in dogs.The stimulation of bilateral stellate ganglion can cause acceleration of blood pressure and heart rate,and the effect of right SG stimulation on blood pressure and heart rate is more obvious than that of the left SG stimulation.