Abstract: Background　The potential hazards of premature atrial contractions（PACs） have been recognized over the years.The ability of clinicians to detect PACs with high frequency and at an earlier stage is particularly important.Ambulatory electrocardiogram（ECG） is the preferred non-invasive examination for such arrhythmias.Although the traditional template-based method（template-based method） has been used for a long time in clinical settings，it cannot meet current clinical needs due to time-consuming.The Lorenz-RR scatter plot with reverse technique（scatter plot method） is a new diagnostic approach that can provide rapid detection and differential diagnosis of PACs.Objective　To summarize the characteristics of the Lorenz-RR scatter plot in patients with non-conducted premature atrial contractions（nPACs），and to further improve the diagnostic accuracy regarding PACs by combining reverse technique with differential diagnosis of type I second degree atrioventricular block（AVB）．Methods　Data obtained from 108 patients with arrhythmia who were treated in the Affiliated Wujin Hospital of Jiangsu University from January 2016 to June 2018 were analyzed retrospectively.Of them，those with nPACs （>100 times/24 h） were included in group A，and those with type I second degree AVB were included in group B.Ambulatory ECG data of group A were analyzed using both template-based and scatter plot methods.PACs，nPACs，paroxysmal atrial tachycardia，premature ventricular contraction，the fastest heart rate，the slowest heart rate，and the total heart rate were analyzed.The slopes of pre and post set lines of the non-conducted scatter plot in group A，along with those of blocked scatter plot in group B were compared，and the symmetry of pre and post set lines about 45 degree isovelocity was also compared for the two groups by using Geometer's Sketchpad.Results　The number of PACs，paroxysmal atrial tachycardia，and ventricular premature contractions detected using the template-based method was less than that detected using the scatter plot method，respectively（P<0.05）．The total number of heart beats detected using the template-based method was higher than that detected using the scatter plot method（P<0.05）．There was a significant difference in the slope of the point set before and after non-conducted PACs in group A or blocked scatterplot in group B（P<0.05）．There was no significant difference between the reciprocal slope of the pre point set and the slope of the post point set of the non-conducted scatter plot in group A（P>0.05）．However，a significant difference was seen between the reciprocal slope of the pre point set and the slope of the post point set of the blocked scatter plot in group B（P<0.05）．Conclusion　The scatter plot method can not only identify nPACs quickly，but can also count their number and improve the detection rate and diagnostic accuracy of PACs，and the ability to differentiate them from type I second degree AVB.

Key words: Atrial premature complexes；Arrhythmias, cardiac；Atrioventricular block；Electrocardiography；Lorenz-RR scatter plot；Reverse technique

摘要： 背景　房性期前收缩（PACs）的潜在危害性已逐渐受到重视。对于频发、提前率大的PACs，其检出率尤为重要，动态心电图是此类心律失常首选的无创检查方法。传统模板分析法（简称模板法）临床运用已久，分析比较耗时，不能满足临床需求；心电散点图及其逆向技术（简称散点图法）是一种新的诊断技术，能对PACs进行快速诊断和鉴别诊断。目的　本文旨在通过对房性期前收缩未下传（nPACs）患者心电散点图的特征进行总结，结合逆向技术与2度Ⅰ型房室传导阻滞（AVB）相鉴别，进一步提高PACs的诊断准确性。方法　回顾性分析2016年1月—2018年6月于江苏大学附属武进医院就诊的心律失常患者108例，nPACs≥100次/24 h患者作为A组，2度Ⅰ型AVB患者作为B组。A组患者的动态心电图数据分别通过模板法及散点图法进行分析，对PACs、nPACs、阵发性房性心动过速、室性期前收缩、最快心率、最慢心率及总心搏数的数量进行比较。运用《几何画板》对A组未下传的前、后点集与B组阻滞前、后点集的直线斜率进行比较，对两组患者前、后点集关于45°等速线的对称性进行比较。结果　模板法PACs、阵发性房性心动过速、室性期前收缩检出数量小于散点图法，总心搏数检出数量大于散点图法（P<0.05）。A组PACs未下传或B组阻滞前、后点集的直线斜率比较，差异有统计学意义（P<0.05）。A组未下传前点集直线斜率倒数与后点集直线斜率比较，差异无统计学意义（P>0.05）；B组阻滞前点集直线斜率倒数与后点集直线斜率比较，差异有统计学意义（P<0.05）。结论　散点图法不仅可以快速识别动态心电图中的nPACs，而且可以统计其数量，提高PACs的检出率和诊断准确性以及与2度Ⅰ型AVB的鉴别能力。

关键词: 心房期前收缩复合征；心律失常, 心性；房室传导阻滞；心电描计术；Lorenz-RR散点图；逆向技术