Abstract：This paper carefully selects three classic cases of blocked arrhythmia, and explores the regularity of their threedimensional Lorenz scatter plots step by step based on the detailed analysis of their twodimensional time scatter plot, Lorenz scatter plot and difference scatter plot. The threedimensional Lorenz scatter plot characteristics of second degree typed Ⅰ and Ⅱ atrioventricular block (AVB), and third degree AVB were analyzed and summarized. The intrinsic correlation of threedimensional Lorenz scatter plot with twodimensional Lorenz scatter plot and difference scatter plot was compared. The results show different features in the scatter plots of second degree typed Ⅰ and Ⅱ AVB, which serves for rapid identification. The Lorenz scatter plot of third degree AVB expresses electrophysiological characteristics of escaped rhythm—relative fixation of escape cycle and reorganization at any time. Its scatter plot is mainly featured by the fact that point set after premature beats or capture is overlapped in the dominant rhythm of constant velocity line, which is symmetrical distributed by premature beat point set and preprematurebeat point set. Methods such as reverse technique and waterfall graphic analysis are usually utilized to judge atrioventricular relationship and identify properties of escaped rhythm. Twodimensional Lorenz scatter plot is equivalent to the xOy and yOz plane of threedimensional Lorenz scatter plot; twodimensional difference scatter plot is equivalent to the xyz plane of threedimensional Lorenz scatter plot with comparatively compact graphs which facilitates its illustration and understanding. The zOx plane is still symmetrically distributed along the constant velocity line.
