Removal of ECG artifacts from EMG signals with different artifact magnitudes by template subtraction

Abstract

This work investigates the performance of eventsynchronous noise cancelling algorithms to separate ECG artifacts from thoracic EMG recordings. In focus are the precise detection of heart beats, the exact time alignment of the QRS segments and the construction of a template QRS signal. Among the utilized methods is a modified structural intensity (SI) approach based on the observation of extrema in low pass filtered versions of the second derivative as a detector. An adoption of this approach is also used to obtain the exact time alignment of QRS segments. Artificial test signals are constructed based on addition of ECG and sEMG with different magnitudes. We show that approaches based on the observation of extrema in different scales yield superior results.

Removal of ECG Artifacts Affects Respiratory Muscle Fatigue Detection—A Simulation Study

“…The combination was performed with different artifact magnitude values in relation to the sEMG power. To quantify this relation, we used the EMG level known from [ 27 ]. It reflects the ratio of RMS sEMG power (of the unmodulated sEMG signal) and peak-to-peak QRS amplitude.…”

“…The threshold is chosen at half of the maximal value of . Instead of an SI scheme with 14,000 scales (as suggested by [ 30 ]), we used an adopted scheme with a reduced set of 28 scales, as already reported in a previous publication [ 27 ]. Furthermore, we also made use of the time alignment fine tuning from [ 27 ].…”

“…Instead of an SI scheme with 14,000 scales (as suggested by [ 30 ]), we used an adopted scheme with a reduced set of 28 scales, as already reported in a previous publication [ 27 ]. Furthermore, we also made use of the time alignment fine tuning from [ 27 ]. This intermediate exact time alignment step refines the time location of the structural intensity-based QRS detector.…”

Advanced Bioelectrical Signal Processing Methods: Past, Present, and Future Approach—Part III: Other Biosignals

“…The problems are the high amplitude of the ECG signal against the EMG signal and the overlapping of their frequency spectra, so it is not possible to use the ordinary filtering methods in order to remove these artifacts. One of the ways is to locate the EMG electrodes as far from the heart as possible [ 26 ].…”

“…However, these methods are often used for their easy implementation. A problem begins in particular during the elimination of noise signals which overlap with the desired EMG signal in the frequency band [ 24 , 26 ]. Table 1 summarizes the most common processing methods of the EMG data.…”