咪达普利对家兔心肌梗死心肌跨室壁动作电位不均一性的影响  

Effects of imidapril on the electrical heterogeneity across ventricular wall in rabbit with myocardial infarction

作　　者：刘昱圻[1] 李泱[1] 高磊[1] 文毅[1] 王士雯[1] 

机构地区：[1]中国人民解放军总医院老年心血管病研究所,100853

出　　处：《临床心电学杂志》2007年第3期200-204,共5页Journal of Clinical Electrocardiology

摘　　要：目的研究咪达普利对陈旧性心肌梗死家兔非梗死区心室肌复极离散度的影响。方法结扎家兔左前降支8周后,记录单相动作电位;采用二步消化法分离左室游离壁3层心肌细胞。用膜片钳全细胞模式记录单细胞动作电位。结果在体和单细胞研究结果均显示,与手术组相比,陈旧性心肌梗死家兔非心梗区心室肌中层的动作电位时程(MAPD90)明显延长(292±28msvs250±26ms,p<0.05),而内膜下和外膜下心肌细胞延长不明显,3层心肌的跨室壁复极不均一性增加。实验结果还显示在体单相动作电位的离散度较单细胞动作电位小。应用咪达普利后其复极不均一性得到改善,室颤阈值上升(13.9±1.3Vvs9.3±1.0V,p<0.05)。应用咪达普利后心肌的组织重构得到改善,复极异质性得到改善,早后除极发生率也明显降低。结论咪达普利可降低家兔非心梗区心室肌复极离散度,这可能是其减少陈旧性心肌梗死恶性心律失常发生的机制之一。Objective To investigate the effects of imidapril on the electrophysiologic heterogeneity of the non-ischemic zone of rabbits after myocardial infarction. Methods Rabbits with myocardial infarction were prepared via left coronary artery ligation and recovered for 8 weeks after the operation. Monophasic action potentials of three layers myocardium in the non-ischemic zone in vivo were recorded. Myocytes were isolated from suben- docardial （Endo）, midmyocardial （M） and subepicardial （Epi） regions of the noninfarcted left ventricular wall and action potentials were recorded using whole-cell patch clamp technique. Results Compared with sham group, MAPD90 of three layers myocardium in previous MI hearts were all prolonged. MAPDg0 of midmyocytes was prolonged most significantly （292：t：28ms vs 250±26ms ,p〈0.05 ） and ventricular fibrillation threshold （VFT ）was decreased （13.9±1.3V vs 9.3±1.0V ,p 〈0.05 ）. After treatment with IMI, the transmural dispersion of repolarization （TDR） was decreased and the VFT was significantly enhanced. Compared with sham group, APD90 of three layer myocytes were all significantly prolonged in previous MI group, especially M, and transmural repolarization heterogeneity（TRH） was significantly increased. After treatment of IMI, TDR was decreased. With 0.5Hz stimulation, the incidence of early after depolarization （EAD） in previous MI group was much higher than that of sham group and IMI-treated group, the EAD incidences of M were higher than those of Epi and Endo in previous MI group. Conclusions Imidapril could reduce the electrophysiologic heterogenities of noninfarcted area in rabbits after myocardial infarction. This effect of imidapril may contribute to its antiarrhythmic efficacy.

关 键 词：咪达普利 心肌梗死 动作电位 复极不均一性 

分 类 号：R96[医药卫生—药理学]