Objective To discuss the characteristics and formation principles of the ECG scattergrams of borderline parallel heart rhythms with repetitive beats

and lay the foundation for the rapid analysis of related cases.Methods Select several classic cases of borderline parallel heart rhythm with repetitive beats

use retrograde technology to analyze the characteristics of the RR interval

and make the mathematical models of the Lorenz scatter plot and the difference scatter plot in the "Geometric Sketchpad". Refining the characteristics of the ECG scatter plot of the junctional parallel heart rhythm with repetitive beats. Results The results show that the JN’ cycle is relatively fixed; the variability of the inter-rhythm of parallel premature beats is much greater than the variability of the sinus rhythm cycle（NN）. Relatively speaking

the NN cycle is constant

the NJ period is a variable

and the mathematical model of the scatter diagram made according to the constant-variable nature of the RR interval is highly consistent with the true diagram. Comparing the model with the real image

it can be concluded that the main features of the ECG scatter diagram with borderline parallel heart rhythm with repeated beating are: JN’ horizontally distributed in the low position; NJN’ horizontally distributed

JN’N vertically distributed; NNJN’

NJN’N

JN’NN are respectively distributed on the Ⅲ quadrant

Ⅱ quadrant

and the positive side of the x-axis

and generally have a three-wheeled structure.Conclusions The ECG scatter diagram of borderline parallel heart rhythm with repetitive beats has strong regularity and obvious characteristics. It is obviously different from the scatter diagram of inserted premature beats. The ECG scatter diagram technology is the secret weapon for rapid analysis of related cases.