Analysis of diaphragm EMG signals: comparison of gating vs. subtraction for removal of ECG contamination

Abstract

The diaphragm electromyogram (EMGdi) conveys information relating to the mechanisms of respiration; however, electrocardiogram (ECG) contamination can compromise the accuracy of data derived from this signal. We examine the EMGdi recorded from anesthetized spontaneously breathing dogs via implanted electrodes to assess the extent of the error introduced by the ECG contamination and the effectiveness of ECG gating in reducing this error. Because ECG subtraction has been shown to generate accurate results for such applications, it is used as the gold standard. Analysis of variance methods are employed to compare results derived from the EMGdi data after ECG subtraction with corresponding results derived from the original data and from the data after ECG gating. Estimates of EMGdi variables obtained by using subtraction and gating techniques were not significantly different, indicating that gating can be employed on these signals to reduce ECG contamination without affecting the accuracy of the derived data. Results also show that at EMG-to-ECG power ratios > 13.3 dB, ECG contamination does not significantly affect estimates of the EMGdi variables.

Removal of the electrocardiogram signal from surface EMG recordings using non-linearly scaled wavelets

“…Both methods provide a simplistic, yet potentially effective, method of ECG artifact removal. However, the gating method does suffer from losing the portions of the EMG signals which overlap with the ECG and is therefore not ideal, especially not for non-stationary signals (Bartolo et al, 1996). The Butterworth filter cuts out parts of the EMG that may contain valuable information contained in the low frequency content of the signal and leads to an increase of the mean frequency.…”

Applications of ICA and fractal dimension in sEMG signal processing for subtle movement analysis: a review

“…The other commonly used techniques to improve the quality of bio signals recordings include spectral filtering, gating and cross-correlation subtraction [11]. Spectral filtering is often not useful due to the overlap of the frequency spectrum of the desired signals and the artefact component.…”

The Polysomnogram Assay: A Method to Represent the Overnight Polysomnogram in a Condensed Format

“…The first step involves reduction of ECG contamination by a technique known as gating (7 ). This is implemented as an appendage to the AECGA mentioned earlier (3), and involves the demarcation of each section of EMG signal containing a QRS complex.…”

“…The EMG signal is then squared and datapoints in each gated section are replaced by the mean of the two adjacent sections of equal duration. The preprocessing is not expected to significantly affect the EMGderived sequences, since even at elevated heart rates, gated sections should account for well below 50% of the signal duration (7 ).…”