国产伊布利特对兔心脏电生理特性时间依赖性影响

Time-dependent effect of ibutilide on rabbit cardiac electrophysiological characteristics

目的观察国产伊布利特对兔心脏电生理作用及其随时间变化的特点。方法健康成年新西兰大白兔20只,麻醉后气管插管,以0.284 mg/kg静脉给药并观察测量给药0,30,60,120,180,240 min右房的有效不应期(AERP)及0,10,15,30,40,60,90,120,180,240 min RR间期、PR间期、PA间期、QRS波时限、QT间期、A-H间期、H-V间期。观察常规剂量以及静脉4～6 mg伊布利特对心律、血压等的影响。结果①伊布利特能显著延长右房的AERP(P<0.05)。但对AERP的频率适应性无明显影响(P>0.05)。②伊布利特对心率有抑制作用,90 min达到最大效应(RR间期最长达272.36±9.43 ms),后RR间期逐渐缩短。③伊布利特在给药后10 min直至240 min均可延长PR间期、QRS波时限、QT间期,以给药后90 min效应最明显。对AH,HV间期无影响。④在给药后2min ST-T形态发生改变,ST段呈上斜型抬高。60 min时T波下降支逐渐显现,9 h ST-T逐渐下降最终呈水平型。⑤常规静脉推注给药未见心律失常,静脉给药4～6 mg时出现频发室性早搏(简称室早)四联律,继续静脉推注2mg,出现频发室早三联律,二联律。结论伊布利特能够减慢心率,延长兔高右房AERP,常规给药剂量下健康兔无心律失常发生。

Objective To observe time-dependent effect of ibutilide on rabbit cardiac electrophysiological characteris- tics. Method Twenty adult and healthy New Zealand rabbits were anesthetized and intubated with a tracheal tube. The RR, PR, PA, QRS, QT, AH, HV intervals were measured after ibutilidc infusion （0,10,15,30,40,60,90,120,180,240 min） and right atrial effective refractory（AERP） were measured after ibutilide infusion（0,30,60,120,180,240 rain） at a dosage of 0. 284 mg/kg. Results ①Ibutilide significantly prolonged the AERP （P 〈 0. 05） and there was not signifi- cantly decrease of rate-dependent effect of AERP（ P 〉 0.05 ）. ②Ibutilide had the significant suppressing effect on the sinus heart rate. The peak response time was 90 rain（ RR = 272.36 ± 9.43 ms） and the heart rate recovered without drug admin- istration. ③The differences of A-H interval and H-V interval at sinus rhythm before and after the administration of ibutilide weren＇t significant （ all P 〉 0. 05）. After injection of ibutilide , the PR, QRS, QT intervals were significantly prolonged af- ter administration in 10 min to 240 rain, the peak response time was 90 min. ④ST-T segment was elevated after administra- tion of ibutilide in 2 rain, resolved in 60 min and disappeared in 9 h. ⑤There were no significant arrhythmia by administra- tion at a dosage of 0.284 mg/kg. The rabbit developed the frequent occurrence of quadrigeminy ,trigeminy and bigeminy of ventricular premature beat after administration at a dosage of 4 -6 mg. Conclusion Ibutilide can reduce the heart rate and prolong the AERP of hight right atrium in rabbit. Routine dosage of ibutilide has no arrhythmia effect on healthy rabbit.