a new automatic qt-interval measurement method for wireless ecg monitoring system using smartphone

Qt-interval prolongation is an important parameter for heart arrhythmia diagnosis. it is the time interval from qrs-onset to the t-end of electrocardiogram (ecg). manual measurement of qt-interval, especially for 12-leads ecg, is time-consuming. hence, an automatic qt-interval measurement is necessary. a new method for automatic qtinterval measurement is presented in this paper, which mainly consists of three parts, including qrs-complex detection, determination of qrs-onset, and t-end determination. the qrs-complex detection is based on the modified pan-tompkins algorithm. the t-end is defined based on region of interest (roi) maximum limit. we compare and test our proposed qt-interval measurement method with reference measurement in term of correlation coefficient and range of 95% loa. the correlation coefficient and the range of 95% loa are 0.575 and 0.290, respectively. the proposed method is successfully implemented in ecg monitoring system using smartphone with high performance. the accuracy, positive predictive, and sensitivity of the qrs-complex detection in the system are 99.70%, 99.78%, and 99.92%, respectively. the range of 95% loa for the comparison between manual and the system’s qt-interval measurement is 0.216. the results show that the proposed method is dependable on the measure of the qt-interval and outperforms the other methods in term of correlation coefficient and range of 95% loa.