异丙肾上腺素致兔心肌肥厚模型的在体心脏电生理研究

目的探讨异丙肾上腺素(Iso)导致兔心肌肥厚在体心脏电生理指标的改变及其与室性心律失常(VAs)的关系。方法 24只兔随机分为Iso组(n=12)和对照组(n=12):Iso组给予异丙肾上腺素(0.3 mg.kg-1.d-1)耳缘静脉注射7天,而对照组注射生理盐水(1 ml.kg-1.d-1)7天。运用单相动作电位记录技术和程控刺激技术,观测在体心室部单相动作电位时程(MAPD)、心室有效不应期(VERP)、自发和诱发的室性心律失常。结果与对照组比较,ISO组MAPD30～MAPD90均延长,而且内外膜MAPD梯度增大,在300,400和500 ms固定频率刺激下VERP明显缩短,VAs发生率升高(P均<0.05)。结论心肌肥厚引起心室部MAPD延长和VERP缩短,VAs发生率增加。

The electrophysiological research of the cardiac hypertrophy induced by isoproterenol in rabbits

Objective To establish a rabbit model with myocardial hypertrophy induced by isoproterenol(Iso) and to investigate the change of cellular electrophysiological characteristics and its relationship with the ventricular arrhythmias(VAs) occured after cardiac hypertrophy.Methods Twenty-four rabbits were randomly divided into Iso group(n=12) and control group(n=12).Iso group received injection of isoproterenol(0.3 mg·kg-1·d-1) via ear vein for 7 days,while the control group injected with saline(1ml·kg-1·d-1) for 7 days.Employing monophasic action potential recording technique and the programmed electrical stimulation technique,monophasic action potential during(MAPD),ventricular effective refractory period(VERP),spontaneous and induced VAs were observed.Results In Iso group,MAPD30-MAPD90 lengthened and VERP shorten significantly.In the Iso group,four of twelve occurred with VAs,but one of twelve occurred with VAs in control group,P<0.05.Conclusion The prolongation of MAPD and the shortening of VERP in the cardiac hypertrophy induced by Iso increase the occurrence of VAs.