[A Digital Filtering Method for Eliminating DC Offset in Ambulatory ECG Signals]

Area of Science:

• Biomedical Engineering
• Signal Processing
• Cardiology

Background:

• Ambulatory electrocardiogram (ECG) acquisition is prone to amplifier saturation due to polarization voltage.
• Traditional analog high-pass filters for artifact removal leave residues or distort low-frequency ECG signals.
• Existing methods struggle to eliminate polarization artifacts without compromising signal integrity.

Purpose of the Study:

• To design and evaluate a Savitzky-Golay (SG) smoothing filter for removing polarization voltage artifacts in ambulatory ECG.
• To achieve drift-free ECG signals while preserving diagnostically important components.
• To overcome the limitations of traditional analog high-pass filters.

Main Methods:

• Developed a Savitzky-Golay (SG) smoothing filter by optimizing parameters: single edge point (M) and polynomial order (p).
• Employed a subtraction algorithm to isolate and remove polarization voltage components from the ECG signal.
• Conducted ECG filtering experiments to validate the filter's performance.

Main Results:

• The designed SG smoothing filter successfully fitted and removed polarization voltage components from ECG signals.
• The filtering process yielded drift-free ECG signals.
• Experimental results confirmed the filter's feasibility and demonstrated that no useful ECG components were lost.

Conclusions:

• The Savitzky-Golay smoothing filter offers an effective solution for eliminating polarization voltage artifacts in ambulatory ECG acquisition.
• This method preserves the integrity of valuable ECG signal components, unlike traditional filtering techniques.
• The SG filter provides a robust and accurate approach to obtaining high-quality ambulatory ECG data.