Govrin O, Sadeh D, Akselrod S, Abboud S
Comput Biomed Res. 1985 Feb;18(1):37-45. doi: 10.1016/0010-4809(85)90005-9.
A combined, cross-correlation procedure for computerized arrhythmia detection is presented. It enables the classification of a wide range of arrhythmia and is based upon the determination of both P and QRS waves. The electrocardiogram (ECG) signal is recorded from external leads, digitized (10 bits of resolution) at 1.28 kHz and processed with a CDC 6600 computer. A normal beat is stored as a reference signal and the onsets of the P wave and the QRS complex are measured for determining the PR, PP, and RR intervals. The combined cross-correlation procedure is carried out between the template and each successive ECG waveform over two time intervals, the first of which includes the P wave and the second, the QRS complex. Prior to this correlation procedure each of the ECG waveforms is filtered through a nonrecursive digital bandpass filter (10 and 100 Hz for low and high cutoff frequencies, respectively). The cross-correlation functions are then calculated by means of a cross spectrum and Fast Fourier Transform algorithm. The maximum value of the normalized cross-correlation function and the time shift providing that value are searched for, allowing (1) determination of the similarity between the present beat and the normal reference beat, allowing for the discrimination of abnormal P and QRS shapes; (2) accurate measurement of the RR, PP, and PR intervals of this subsequent waveform. Applying this method enables a reliable detection of a wide variety of arrhythmia.
本文提出了一种用于计算机心律失常检测的联合互相关程序。它能够对多种心律失常进行分类，并且基于P波和QRS波的测定。心电图（ECG）信号从外部导联记录，以1.28kHz的频率进行数字化（分辨率为10位），并使用CDC 6600计算机进行处理。正常心跳被存储为参考信号，并测量P波和QRS复合波的起始点，以确定PR、PP和RR间期。联合互相关程序在模板与每个连续的ECG波形之间的两个时间间隔内进行，第一个时间间隔包括P波，第二个时间间隔包括QRS复合波。在进行此相关程序之前，每个ECG波形都通过一个非递归数字带通滤波器进行滤波（低截止频率和高截止频率分别为10Hz和100Hz）。然后通过互谱和快速傅里叶变换算法计算互相关函数。搜索归一化互相关函数的最大值以及提供该值的时间偏移，从而（1）确定当前心跳与正常参考心跳之间的相似度，以便区分异常的P波和QRS波形状；（2）准确测量后续波形的RR、PP和PR间期。应用此方法能够可靠地检测多种心律失常。
