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目的：利用Poincare 散点图进行t 波交替检测，不仅从形态上找到检测标准，进一步研究散点中有效的定量指标。方法：以 European ST-T Database 标准心电数据库和MIT-BIH 心律失常数据库的心电信号作为检测对象，以128 个连续心拍的t 波中的7 个点为检测数据，相邻心拍t 波差分后组成新序列，并由差分序列作出散点图，观察散点形态。根据形态区别和t 波交替的幅值变化特点，利用个散点到x+y=0 直线的距离均值作为定量检测指标D0，为避免不同心电信号幅值影响，D0 除以RQ 峰值差为最终指标D，找出合适阈值判定是否存在t 波交替，并与谱分析法的检测结果比较分析。结果：①从Poincare 散点图形态上，存在t 波交替的散点图与正常t 波存在明显区别，存在t 波交替则散点集中在以x+y=0 为轴线的附近，形成类似椭圆的狭长形状；而正常t 波形成的散点会以原点为中心均匀分布，散点形态为圆形。②由t 波交替的特点和散点图形态可知，定量检测指标D 越小，就越有可能存在t 波交替。经过大量仿真测试和谱分析法的比较，规定检测标准为，当D<=35uv 时，存在t 波交替;指标D 与谱分析法的结论相吻合，并且两种方法的判定结果由kappa 一致性检验，一致性程度好，进一步说明D 指标具有优越的敏感性，是t 波交替检测的有效指标。结论：Poincare 散点图的散点分布形态和散点到x+y=0 轴线的距离均值分别是是t 波交替有效的定性和定量检测指标。

英文摘要:

Objective: To research the effective indexes of Poincare scatter in the detection of T-wave alternans (TWA), not only form the geometric pattern, but also from the quantitative index. Methods: Continuous 128 Beats electrocardiosignal(ECG) from MIT/BIH Arrhythmia database and European ECG ST-T database was read, and 7 sampling points from every t wave were selected to make a initial sample series. A new sequence with subtraction between adjacent beats of initial samples was used to draw a Poincare scatter. According to the different geometric patterns and the peculiarity of TWA, a new quantitative index was defined as D0 that was the mean distance from each point to the straight line x+y=0. To avoid the influence made by amplitude from different ECG, the final index D was that D0 divided the difference between Q and R peaks. Then D was compared with the results of spectral method (SM)and appropriate threshold value was selected to recognize TWA. Results: ①The Poincare maps of ECG with TWA were greatly different from those of the normal. If there were TWA , the points mainly located in a long and narrow area which was near the straight line x+y=0.While normal ECG would show us a evenly distributed round whit the origin as the center. ② The likelihood of TWA existing increased with D value diminution. After abundant experiment, the standards were defined as follow: When mean distance D<=35uv, there was TWA .A significant coherence was found between D the Stwa though kappa consistency test. Conclusion: Poincare scatter is a good method for the detection of TWA, and the geometric pattern and the mean distance D are effective qualitative and quantitative indexes.

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