Tikkanen P E, Sellin L C, Kinnunen H O, Huikuri H V
Department of Physical Sciences, University of Oulu, Finland.
Med Eng Phys. 1999 Jan;21(1):15-25. doi: 10.1016/s1350-4533(99)00018-1.
The ambulatory electrocardiogram (ECG) is an important medical tool, not only for diagnosis of adverse cardiac events, but also to predict the risk of such events occurring. The 24-hour ambulatory ECG has certain problems and drawbacks because the signal is corrupted by noise from various sources and also several other conditions which may alter the ECG morphology. We have developed a Windows based program for the computer analysis of ambulatory ECG which attempts to address these problems. The software includes options for importing ECG data, different methods of waveform analysis, data-viewing, and exporting the extracted time series. In addition, the modular structure allows for flexible maintenance and expansion of the software. The ECG was recorded using a Holter device and oversampled to enhance the fidelity of the low sampling rate of the ambulatory ECG. The influence of different sampling rates on the interval variability were studied. The noise sensitivity of the implemented algorithm was tested with several types of simulated noise and the precision of the interval measurement was reported with SD values. Our simulations showed that, in most of the cases, defining the end of QT interval at the maximum of the T wave gave the most precise measurement. The definition of the onset of the ventricular repolarization duration is most precisely made on the maximum or descending maximal slope of the R wave. We also analyzed some examples of time series from patients using power spectrum estimates in order to validate the low level QT interval variability.
动态心电图（ECG）是一种重要的医学工具，不仅用于诊断不良心脏事件，还用于预测此类事件发生的风险。24小时动态心电图存在一些问题和缺点，因为信号会受到来自各种来源的噪声以及其他可能改变心电图形态的多种情况的干扰。我们开发了一个基于Windows的程序，用于对动态心电图进行计算机分析，旨在解决这些问题。该软件包括导入心电图数据的选项、不同的波形分析方法、数据查看以及导出提取的时间序列。此外，模块化结构允许对软件进行灵活的维护和扩展。使用动态心电图记录仪记录心电图，并进行过采样以提高动态心电图低采样率的保真度。研究了不同采样率对间期变异性的影响。用几种类型的模拟噪声测试了所实现算法的噪声敏感性，并报告了间期测量的精度（以标准差表示）。我们的模拟表明，在大多数情况下，将QT间期的终点定义为T波的最大值可得到最精确的测量。心室复极持续时间起点的定义最精确地基于R波的最大值或最大下降斜率。我们还使用功率谱估计分析了一些患者的时间序列示例，以验证低水平的QT间期变异性。
