Department of Geratology, Zhongnan Hospital of Wuhan University, Wuhan, China.
J Cardiovasc Med (Hagerstown). 2012 May;13(5):313-8. doi: 10.2459/JCM.0b013e328352249d.
The current study aims to explore the effect of ramipril on the occurrence of ventricular arrhythmias and its possible mechanism after myocardial infarction (MI) in rabbits.
A total of 24 rabbits were divided into three groups: the sham operation group (SHAM), the MI group, and the ramipril group (RAM). All groups were subjected to thoracotomy under sterile conditions; the MI and RAM groups underwent ligation of the left anterior descending coronary artery. On the second day after surgery, the RAM group was given ramipril (1 mg/kg per day). The rabbits in each group were fed for 12 weeks. The monophasic action potentials of the epicardium, mid-myocardium and endocardium in each group were, respectively, recorded before the MI and at 12 weeks after the MI. Meanwhile, the episodes of ventricular tachycardia or fibrillation (VT/VF) induced by procedure stimulations were counted, and the changes in L-type Ca flux (Ica-L) were recorded by means of the whole-cell patch-clamp technique.
The episodes of VT/VF were decreased in the RAM group after MI. At 12 weeks after MI, the transmural dispersion of repolarization (TDR) in the MI group was prolonged significantly compared with the SHAM and RAM groups. The density of Ica-L in the MI group was significantly lower than that any other group.
Ramipril manifestly decreases the incidence of VT/VF after MI in rabbits, and the mechanism may be associated with its inhibitory effect on electrical remodeling after MI.
本研究旨在探讨雷米普利对兔心肌梗死后室性心律失常发生的影响及其可能机制。
将 24 只兔随机分为三组：假手术组（SHAM）、心肌梗死组（MI）和雷米普利组（RAM）。所有组均在无菌条件下进行开胸手术；MI 组和 RAM 组结扎左前降支冠状动脉。手术后第 2 天，RAM 组给予雷米普利（1mg/kg/天）。各组兔均喂养 12 周。分别记录各组兔术前和心肌梗死后 12 周的心外膜、心肌中层和心内膜单相动作电位。同时，通过程序刺激计数室性心动过速或颤动（VT/VF）的发作次数，并通过全细胞膜片钳技术记录 L 型钙流（Ica-L）的变化。
心肌梗死后 RAM 组 VT/VF 发作次数减少。心肌梗死后 12 周，MI 组跨壁复极离散度（TDR）明显延长，与 SHAM 组和 RAM 组相比差异有统计学意义。MI 组 Ica-L 密度明显低于其他组。
雷米普利明显降低兔心肌梗死后 VT/VF 的发生率，其机制可能与其对心肌梗死后电重构的抑制作用有关。
