伊布利特对犬心率抑制与终止心房扑动机制的初步探讨  

The study of inhibiting heart rate and rapidly terminating atrial flutter of ibutilide on canine

作　　者：孙健玲[1] 李小鹰[1] 郭继鸿[2] 刘鹏[2] 张萍[2] 易忠[2] 

机构地区：[1]解放军总医院老年心内科,北京100853 [2]北京大学人民医院心内科电生理室

出　　处：《中华心血管病杂志》2009年第10期920-924,共5页Chinese Journal of Cardiology

基　　金：国家自然科学基金（30471710）;北京市自然科学基金（7032030）;首都医学发展科研基金（20023036）

摘　　要：目的观察伊布利特对犬心房与心室电生理特性的作用特点，初步探讨其终止心房扑动（房扑）的机制。方法18只成年健康雄性杂种犬，麻醉后气管插管，开胸并缝合电极，伊布利特按0．10mg／kg静脉推注给药，观察给药前后心率、房内与房间传导时间、峡部缓慢传导区传导速度、各部位不应期的变化。结果伊布利特对心率有明显的抑制作用，作用的高峰时间在给药后20～30min，2h后心率基本恢复到用药前的水平。实验中，1只犬在给药后出现长达5s的窦性停搏；1只犬在给药后5min出现房室结2：1下传。伊布利特能显著延长心房肌、心室肌以及肺静脉的不应期（P〈0．05），但对房内、房间以及峡部的传导作用影响不明显（P〉0．05）。结论伊布利特可明显减慢窦性心律，对窦房结的自律性有一定的抑制作用，对房室结的功能有一定的抑制作用。伊布利特终止房扑的机制可能是由于该药造成不应期延长，使折返环可激动间隙兴奋性降低，进而使波峰不能向前推进，终止房扑。其房扑折返环传导的减慢可能不是房扑终止的主要作用。Objective To observe the electrophysiological effects of ibutilide on canine and to explore the potential mechanisms of ibutilide on terminating atrial flutter. Methods Eighteen mongrel dogs were anesthetized and intubated. The heart was exposed through thoracotomy for electrodes implantation. The electrophysiologic variables （heart rate, the conduction of intraatrium and interatrium, the conduction ratio of isthmus, the effective refractory period） were measured in the absence or presence of ibutilide （ 10 minute infusion with 0. 10 mg/kg ibutilide, 30 minutes later with a maintaining dose of 0. 01 mg/min）. Results Ibutilide significant suppressed sinus atrial node function, the peak effect was observed at 20 -30 min post drug infusion and heart rate returned to normal at 2 hours post infusion. Post ibutilide infusion, 1 canine developed sinus pause for 5 seconds and 2：1 atrioventricular conduction block was evidenced in another canine. The atrial, ventricular and pulmonary vein effective refractory periods were all significant prolonged （ all P 〈 0. 05 ） post ibutilide infusion. However, conduction of intraatrium, interatrium and isthmus remained unchanged post ibutilide infusion （ all P 〉 0. 05 ）. Conclusions Ibutilide could suppress sinus atrial node and the atrioventricular node function. The mechanism of ibutilide on rapidly terminating atrial flutter might be related to the prolongation of the refractory periods which might then result in the reduction of the whole excitable gap of the reentrant circuit and induce proceed inability of reentrant wavefront.

关 键 词：心率 心房扑动 电生理学 伊布利特 

分 类 号：R686[医药卫生—骨科学]