Abstract：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, V1-V6, V3R-V5R and V7-V9 were retrieved, and then a fixed conversion coefficient CR-Vi=Vi－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. ResultsBoth 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 noninfarctionrelated wide and deep Q waves and nonischemic T wave inversion, known as the socalled 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.
