犬冠状窦肌组织在左右心房间电传导中的作用

The role of coronary sinus musculature on electrical conduction between left atrium and right atrium in isolated canine heart

目的探讨犬冠状窦肌组织在左右心房问电传导中的作用。方法16只犬离体心脏在Langendorff灌流下通过冠状窦口电极、冠状窦远端电极和左房侧壁电极进行程控刺激，观察左右心房间电传导。结果冠状窦口S1S1刺激可记录到冠状窦双电位，传至远端的时间为（44±21）ms，4例S1S2刺激使左房传导顺序改变。冠状窦远端S1S1刺激仅3例诱发电传导，传导时间为（41±15）ms，1例S1S2刺激使左房传导顺序改变。左房侧壁S1S1刺激电活动由冠状窦中部向两端传导。冠状窦口、冠状窦远端、左房侧壁S1S2刺激有效不应期分别为（122±19）ms、（114±12）ms（n=3）和（107±17）ms（P〉0．05），进入有效不应期前左房侧壁刺激的电传导阻滞率为0，冠状窦口刺激电传导阻滞率为25％。结论冠状窦内存在一条左右心房间的特殊的传导束，可能是一定条件下诱发并维持房性心律失常的心房间传导通路之一。

Objective To investigate electrophysiological characteristics of the coronary sinus musculature and explore its role on electrical conduction between left atrium and right atrium in isolated canine heart. Method The electrical connections between coronary sinus, left atrium and right atrium were detected by programmed stimulation delivered at coronary sinus ostium, distal coronary sinus and lateral wall of left atrium in a Langendorff model of canine. Results During stimulation delivered at coronary sinus ostium and distal coronary sinus, posterior wall of left atrium was firstly activated by electronic signal through coronary sinus musculature,the conduct time of coronary sinus ostium stimulation and distal coronary sinus stimulation were （44 ± 21 ） ms and （41 ± 15 ） ms, respectively. During stimulation delivered at lateral wall of left atrium, electronic signal was firstly observed in coronary sinus. During premature stimulation, conduction blockade of coronary sinus to left atrium was evidenced in parts of hearts, but electronic conduction of left atrium to right atrium remained stable. The ERP at the different stimulation sites of coronary sinus ostium and distal coronary sinus, posterior wall of left atrium were（ 122 ± 19） ms, （ 114± 12） ms（ n = 3 ） and （ 107±17 ） ms（ all P 〉 0.05 ）. Conclusion A conduction way connecting left and right atria exists in coronary sinus which might play an important role on inducing and maintaining atrial arrhythmias under certain pathological conditions.