单相动作电位同步记录电极的建立和应用

目的　设计跨心室壁三层单相动作电位(MAP)同步记录电极,为跨心室壁复极异质性的在体研究提供有效途径。方法　以改造的 12 号不锈钢针头为外鞘,按先后顺序将彼此绝缘的外、中、内膜电极依次与外鞘组装,经过绝缘性、电导通性检测后,分别在体记录了兔、犬跨左心室壁内、中、外膜心肌的单相动作电位和心电图。结果　①兔左心室前壁内、中、外三层单相动作电位形态各不相同,中、外膜层 MAP复极起始部分具有典型的“峰和圆顶”特征,内膜层MAP复极过程中不存在明显切迹;在心率为272 次/min时,兔左心室内、中、外层心肌动作电位时程分别为 140、140、130 ms;动作电位幅度分别为17.5、19.31、11.51 mV。②犬中、外膜层心肌复极起始部分具有“峰和圆顶”特征,中膜层心肌1期切迹不如外膜层典型,内膜层心肌复极1期仅有小的切迹;心率为 139 次/min时,犬内、中、外层心肌动作电位时程分别为230、250、200 ms;动作电位幅度分别为46.33、66.41、43.30 mV。结论　自制单相动作电位能清晰、有效的记录在体动物跨心室壁各层的动作电位,可用于跨心室壁复极异质性的在体实验研究。

Preparation and application of simultaneous-recording monophasic action potential electrode

Objective To provide an effective method for in vivo research on transmural heterogeneity of repolarization through preparation and application of the monophasic action potential (MAP) electrode by which the MAPs of transmural three-layer myocardium could be recorded concurrently. Methods The No.12-stainless pinheads were reconstructed into sheathes, and then the electrodes were fixed in the sequence of epicardium, mid-layer myocardium, endocardium into simultaneous-recording MAP electrode. After the examination of electrical access and insulation, the MAPs of endocardium, mid-layer myocardium, epicardium in left ventricles and ECG of rabbits, canines were recorded in vivo, respectively. Results ① The morphological features of MAP of the transmural layers of rabbit left ventricles were different from each other. The MAPs of mid-layer myocardium and epicardium showed a typical character of “peak and dome” in phase 1 during repolarization, which didn't exist in endocardium. The MAP durations of endocardium, mid-layer myocardium, epicardium were 140ms,140ms and 130ms at the heart rate of 272 per minute; The amplitudes of MAPs were 17.5,19.31 and 11.51mV, respectively. ② There were characters of “peak and dome” in the initial repolarization of canine left ventricles. The notches of mid-layer myocardium during phase 1 were not as typical as those in epicardium, and there were only some small notches present in endocardium during phase 1; The MAP durations were 230ms, 250ms and 200ms in endocardium, mid-layer myocardium, epicardium in canine left ventricles at the heart rate of 139 per minute; Amplitudes were 46.33, 66.41 and 43.30mV, respectively. Conclusion Transmural MAP signals can be recorded clearly and effectively with self-made MAP electrode. This electrode can be used in in vivo study for transmural heterogeneity of repolarization.