Abstract

A significant amount of studies are aimed at investigating the mechanisms of occurrence and ways to prevent supraventricular arrhythmias, in particular, atrial fibrillation. Its occurrence in most cases is associated with the electrophysiology’s features of the myocardial tissue of pulmonary veins (PVs), the most important of which is the tendency of this tissue to form ectopic automaticity. However, there is no information to date about the existence of strains of mice that are genetically predisposed to arrhythmias due to ectopic automaticity in the supraventricular myocardium. Nevertheless, rodents are becoming an increasingly frequent model object for basic electrophysiological research. In connection with the foregoing, the purpose of this work was to study the bioelectric properties of the PVs and atrial myocardium as well as to identify the electrical activity’s characteristics of the heart in F1-generation mice of interlinear hybrids of the C57Bl/6 and CBA strains (B6CBAF1). In ex vivo experiments, action potentials (APs) were recorded in tissue preparations of atrial myocardium and PV myocardium of B6CBAF1 mice and control BALB/c mice, using the standard microelectrode technique. In in vivo experiments in B6CBAF1 and BALB/c mice, standard electrocardiogram (ECG) parameters were recorded and calculated. In 80% of the experiments, the PV myocardium in B6CBAF1 mice was observed to have permanent ectopic automatic activity. In 55% of cases, spontaneous APs (SAPs) were characterized by oscillations of the membrane potential during repolarization, owing to which the duration of APs reached 1–20 s. SAPs in B6CBAF1 mice were observed not only in PVs but also in the left atrial myocardium in 80% of the experiments. In BALB/c mice, in contrast to B6CBAF1, no prolonged episodes of SAPs or AP repolarization anomalies were observed in any of the experiments either in PVs or the atrial myocardium. When registering ECG in B6CBAF1 mice, as in BALB/c, neither rhythm disturbances nor any significant deviations of the main parameters of the ECG, except for an increased heart rate, were detected. It is possible that B6CBAF1 mice are the first interlinear hybrid to be detected whose supraventricular myocardium is predisposed to arrhythmogenic automaticity due to ectopic and trigger activity.

中文翻译：

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B6CBAF1壁画菌株心脏中的室上心肌揭示由于异位自动性和触发的活动的基因确定的心律失常特性。

摘要

大量的研究旨在调查发生机制和预防室上性心律失常，特别是房颤的方法。在大多数情况下，它的发生与肺静脉（PVs）心肌组织的电生理特征有关，其中最重要的是该组织形成异位自动的趋势。但是，到目前为止，还没有关于由于室上心肌异位自动而导致基因易患心律失常的小鼠品系的信息。然而，啮齿动物正成为基础电生理研究中越来越常见的模型对象。结合前述，这项工作的目的是研究PVs和心房心肌的生物电特性，并确定C57Bl / 6和CBA品系（B6CBAF1）的线性杂种的F1代小鼠的心脏电活动特征。在体外实验中，使用标准微电极技术在B6CBAF1小鼠和对照组BALB / c小鼠的心房和PV心肌的组织制剂中记录了动作电位（APs）。在体内在B6CBAF1和BALB / c小鼠的实验中，记录并计算了标准心电图（ECG）参数。在80％的实验中，观察到B6CBAF1小鼠的PV心肌具有永久性异位自动活动。在55％的情况下，自发AP（SAP）的特征是复极化过程中膜电位的振荡，因此AP的持续时间达到1-20 s。在80％的实验中，不仅在PV中而且在左心房心肌中都观察到B6CBAF1小鼠中的SAP。与B6CBAF1相比，在BALB / c小鼠中，无论在PV还是在心房心肌中，在任何实验中均未观察到SAP或AP重新极化异常的延长发作。与BALB / c一样，在B6CBAF1小鼠中注册ECG时，无论是心律失常还是ECG主要参数的任何明显偏差，除心率增加外，均被检测到。B6CBAF1小鼠可能是第一个被检测到的线间杂种，由于异位和触发活动，其室上心肌易致心律失常。