CR导联心电图的原理及临床应用

Principles and clinical applications of CR lead ECGs

目的探讨CR导联心电图的原理及临床应用。方法CR导联系统是有共同负极的双极胸导联系统,其共同负极是右上肢(R),正极是胸部某点(C),多选V导联各点。获取CR导联心电图的方法有两种:一是利用常规心电图机实采,四个肢体电极全接右上肢,胸导联电极正常连结;二是基于常规心电图数据通过导联转换获取,首先调取aVR、V_(1)-V_(6)、V_(3R)-V_(5R)、V_(7)-V_(9)等导联的原始数据,再利用固定的转换系数CR-V_(i)=V_(i)-2/3 aVR计算目标导联(使用Python语言在Pycharm编译环境下实现算法),最终转换完成后画图。结果实采法与转换法获取了相同的CR导联心电图,但与相应的Wilson导联心电图相比,左胸导联的CR导联心电图形态类似而波幅略大,右胸导联CR导联心电图与Wilson导联心电图波幅相近但形态截然不同:前者P波清晰,QRS波群主波向上、无宽深的Q波,T波直立;后者P波较低,QRS波群主波向下,可出现非梗死性宽深Q波及非缺血性T波倒置,即所谓的右心室盲区。结论CR导联心电图开放了右心室盲区,实现了对左、右心室的平等探测,为临床提供了更有价值的心电学形态信息,弥补了Wilson胸导联系统的不足,值得推广普及。

Objective To explore the principles and clinical applications of CR lead ECGs.Methods The CR lead system is a bipolar chest lead system with a common negative electrode.The right upper limb(R)is its common negative electrode,the positive electrode is a point on the chest(C),and each point of V leads were multiply chosen.We can obtain CR lead ECGs by the following two methods.The first method is to make direct acquisition by a conventional ECG machine,with all four limb electrodes connected to the right upper limb and the chest lead electrode connected normally.The second method is to obtain CR lead ECGs through lead conversion based on conventional ECG data.First,the original data of leads such as aVR,V_(1)-V_(6),V_(3R)-V_(5R) and V_(7)-V_(9) were retrieved,and then a fixed conversion coefficient CR-V_(i)=V_(i)-2/3aVR was used to calculate the target lead(the algorithm was implemented under the compiling environment of Pycharm in Python language);finally,the conversion is completed and plotted.Results Both the direct acquisition method and the conversion method obtained the same CR lead ECGs.However,compared with the corresponding Wilson lead ECG,CR lead ECG in the left chest lead had a similar morphology but slightly great wave amplitudes while CR lead ECG in the right chest lead had similar wave amplitudes but distinctly different wave morphology.The CR lead ECG in the right chest lead had a clear P wave,an upward QRS complex with no wide or deep Q wave,and an upright T wave.Wilson lead ECG had a lower P wave,a downward QRS complex,and could exhibit non-infarction-related wide and deep Q waves and non-ischemic T wave inversion,known as the so-called right ventricular blind zone.Conclusion CR lead ECG opens up the right ventricular blind zone,and achieves equal detection of the left and right ventricles,providing more valuable ECG morphological information for clinical practice and compensating for the limitations of the Wilson chest lead system.It is worthy of being promoted and popularized.