胺碘酮对心力衰竭犬心室电生理特性的频率依赖性影响

Frequency dependent effects of amiodarone on ventricular electrophysiology in right ventricular rapid pacing induced heart failure canine models

目的研究胺碘酮对快速右心室起搏致充血性心力衰竭（ＣＨＦ）犬模型心室电生理特性的频率依赖性影响。方法３２只犬随机分成正常对照组（ｎ＝７）、正常服胺碘酮组（ｎ＝７）、ＣＨＦ组（ｎ＝９）及ＣＨＦ服胺碘酮组（ｎ＝９）。服胺碘酮组给予口服胺碘酮３００ｍｇ／ｄ、４～５周。采用快速右心室起搏（２４０次／分、４～５周）制作ＣＨＦ模型。应用心脏电刺激和单相动作电位记录技术测定电生理参数。结果胺碘酮对正常及ＣＨＦ犬的心室单相动作电位时程（ＭＡＰＤ９０）、有效不应期（ＶＥＲＰ）的影响及增加ＶＥＲＰ／ＭＡＰＤ９０比值的作用无频率依赖性，延长心室传导时间的作用呈频率依赖性。结论胺碘酮对ＣＨＦ犬心室电生理效应的频率依赖性与对正常犬相类似。

Objective To investigate the frequency dependent effects of amiodarone on ventricular electrophysiology in right ventricular rapid pacing induced congestive heart failure(CHF) canine models. Methods Thirty two dogs were randomly allocated into four groups: Group 1( n =7) served as controls. Group 2 ( n =7) were given amiodarone orally 300 mg a day for 4 5 weeks. Group 3( n =9) were the CHF models induced by right ventricular rapid pacing (240 pulses·min 1 for 4 5 weeks). Group 4( n =9) were the CHF models given amiodarone orally 300mg a day for 4 5 weeks. The electrophysiological variables were evaluated by the techniques of standard electric stimulation and monophasic action potential (MAP) recording.Results The effects of amiodarone on ventricular MAP duration (MAPD 90 ) and effective refractory period (VERP) were not frequency dependent in normal and CHF dogs. There were also no frequency dependent effects on the increase of the ratio of VERP to MAPD 90 (VEPR/MAPD 90 ). The prolongation of ventricular conduction time was frequency dependent.Conclusion The frequency dependent effects of amiodarone on ventricular electrophysiology in CHF dogs were similar to that in normal dogs.