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目的:探讨增强的肾上腺素能作用对兔心律失常的影响。方法:新西兰纯种大耳白兔30只随机分为三组各10只,分别腹腔注射生理盐水1 mL、去甲肾上腺素(NE)0.5 mg/kg和NE 1.0 mg/kg,一日两次,连续15天。在体同步记录各组三层心肌单相动作电位(MAP)复极90%的时限(MAPD_(90))、跨比复极离散度(TDR)及程序刺激诱发室性心律失常情况。再静脉给予异丙肾上腺素(Iso)6 μg/(kg·min),观察急慢性肾上腺素能重叠效应对程序刺激诱发心律失常的影响。结果:(1)三组之间MAPD_(90)及TDR的比较元显著性差异。(2)高剂量组与低剂量组中层心肌的MAP 2期拱顶消失。(3)程序刺激下,早期后除极(EAD)或/和延迟后除极(DAD)及室性早搏在实验组均有增加。静脉给予Iso后与对照组比较,实验组恶性心律失常发生均有增加,但仅高剂量组P<0.05。结论:增强的肾上腺素能作用可引起兔心室肌复极电活动改变,并可导致室性心律失常增加,但对三层心肌的MAPD_(90)和TDR影响不明显,其致室性心律失常机制可能与EAD/DAD增加有关。
Objective: To investigate the effect of enhanced adrenergic effect on arrhythmia in rabbits. Methods: Thirty New Zealand purebred white rabbits were randomly divided into three groups of 10 rats. The rats were injected intraperitoneally with normal saline (1 mL), norepinephrine (NE) 0.5 mg / kg and NE 1.0 mg / kg twice daily For 15 consecutive days. The ventricular arrhythmia was induced by MAPD 90% (MAPD 90), across the complex repolarization dispersion (TDR) and program stimulation in vivo. Intravenous isoproterenol (Iso) 6 μg / (kg · min) was administered to observe the effect of acute and chronic adrenergic overlay on the process-induced arrhythmia. Results: (1) The MAPD_ (90) and TDR between the three groups were significantly different. (2) The MAP 2-phase vault disappeared in the middle myocardium of high-dose group and low-dose group. (3) EEG and / or post-depolarization (DAD) and premature ventricular contractions were all increased in experimental group under the stimulation of program. Compared with the control group, the incidence of malignant arrhythmia in experimental group increased after intravenous administration of Iso, but only in high dose group (P <0.05). CONCLUSION: The enhanced adrenergic effect may induce the alteration of ventricular repolarization activity in rabbits and lead to the increase of ventricular arrhythmia, but it has no obvious effect on the MAPD 90 and TDR of the three layers of myocardium. The ventricular arrhythmia Mechanisms may be related to the increase in EAD / DAD.