GPRS移动式心电监护系统的QRS波实时检测算法

Algorithm of real-time QRS complex detection for the GPRS mobile ECG telemonitoring system

目的探讨GPRS移动式心电监护系统ECG信号QRS波的实时检测算法。方法采用四点平均对CM5导联的ECG信号进行滤波,再对ECG信号的一、二阶差分值进行平滑处理,利用ECG信号的二阶差分值极小值和一阶差分过零点在较短的时间窗内实现QRS波精确定位,并设计了具有自学习和自适应功能的信号检测门限。结果算法能抑止多种噪声对ECG信号的影响,将搜索的时间窗宽度缩小到0·02s以下,且算法只具有多项式的复杂度;经过临床测试,动态ECG信号进QRS波检测准确率可达99·8%以上。结论该算法适合于移动心电监护系统QRS波的实时检测和分析。

Objective To develop a real-time QRS complex detection algorithm of dynamic ECG signals for the GPRS mobile telemonitoring system. Methods Before the first and second derivatives of ambulatory ECG signals were processed by moving average method, the signals sampled from CM5 monitoring lead were filtered with the average of continuous four ECG sample signal points. The R waves could be detected precisely by local minima of second derivatives and Q & S waves were located correctly by cross-zero points of first derivatives of ambulatory ECG signals in a short-time searching windows. The QRS recognition thresholds, which could revise themselves according to the detected values and vary with the analyzing signals, were designed in this paper. Results With a polynomial computation complexity, the novel algorithm insensitive to baseline draft and noise caused by mobile communication filtered power-line interference and most of muscle noise and reduced the search time below 0.02 s during detecting each Q wave, R wave and S wave. For the normal and clinical patients, this algorithm correctly detected up to 99.8% of the QRS complex of ambulatory ECG signals. Conclusion The algorithm can meet the need of real-time QRS complex detection and analysis for the GRRS mobile ECG telemonitoring system.