Real-time Detection of Feature Waves for Mobile Cardiac Telemonitoring System

摘要

Mobile cardiac telemonitoring system can provide patients who may stay out of hospital with cure, nurse,rninstruction and other service in time by GPRS or CDMA communication network through which real-time ambulatoryrnECG signals are transported to monitoring center in hospital. It is necessary to rapidly detect the feature waves such asrnQRS complex, P wave and T wave of ECG signals to aid monitoring person to make medical decision promptly. The novelrnalgorithm that filters power-line interference and most of muscle noise and is insensitive to baseline draft and noise causedrnby mobile communication, has been developed in this paper. It accurately detects real-time QRS complex based on localrnminima of second derivatives and cross-zero points of first derivatives of ambulatory ECG signals. The QRS recognitionrnthresholds, which can revise themselves according to the detected values and vary with the analyzing signals, are designedrnespecially. The detection interval and threshold of P waves and T waves are determinate by the value of RR intervals andrnnoise estimate of ECG signals in this period. The local linear transform algorithm is established to test the magnitude andrndetermine the direction of the two feature waves. For the normal and clinical patients,the novel method with computationrncomplexity of polynomial order correctly detects up 90 percent of feature waves of ambulatory ECG signals and has beenrnsuccessfully applied to real-time analysis of signals in mobile ECG telemonitoring system.