Enhancing the precision of ECG baseline correction: Selective filtering and removal of residual error

Reemergence of the problem of baseline correction is related to recent adva ncements in the electrocardiographic (ECG) analysis of brat-to-beat repolar ization changes which play an important role in risk assessment and the pre diction of sudden cardiac death. These alterations often have an amplitude of a few microvolts and duration of several milliseconds and their detectio n requires special accuracy of baseline estimation. Using detailed analysis of various types of residual errors we designed a two-step procedure for s elective filtering of ECG and removal of residual error with minimal distor tion of cardiac complexes and tested this approach on 100 simulated and 210 real ECG signals. Application of this procedure provided a twofold reducti on in the error of baseline estimation and T-wave amplitude measurements co mpared to high-pass filtering. Selective application of this approach to th e segments with low baseline drift allowed analysis of low-amplitude, beat- to-beat changes in repolarization during more than 70% of the recording tim e, (C) 2000 Academic Press.