Extracting Strategy for Interval of ST Segment in ECG Based on Least Absolute Deviation Estimation

Objective To propose a new strategy basing on least absolute deviation estimation(LADE) for extracting the interval of ST segment in ECG.Methods Based on the detected position inside QRS complexes,the LADE and deviation of linear segments from this point was calculated backward and a basic linear segment was checked out.Upon this,the offset of QRS complex was determined by hypothesis testing.The T wave afterwards was classified into 4 groups under LADE.Q point and Q regression line were decided according to different criterion under different groups.After Q point,the deviation between ECG data and Q regression line determined the onset of T wave.Thus the interval of ST segment was extracted.Results The strategy was verified by all the records from QT database,in which the T wave onset was marked by cardiologists,and reached the average error of 2.4 ms on 1412 ST segment marked by cardiologists.Conclusion The strategy of LADE-based interval extraction for ST segment is feasible.