Power-line interference cancellation in ECG signals

Area of Science:

• Biomedical Engineering
• Signal Processing

Background:

• Power-line interference is a common artifact in electrocardiogram (ECG) recordings.
• Digital notch filters are widely used but can negatively impact crucial ECG waveform components like the QRS complex.
• Existing methods for interference cancellation may struggle with variable amplitude and frequency.

Purpose of the Study:

• To evaluate the effectiveness of notch filters versus a subtraction procedure for power-line interference cancellation in ECG signals.
• To address the limitations of digital notch filters in preserving ECG signal integrity.
• To develop a robust method for eliminating power-line interference, adaptable to various device constraints.

Main Methods:

• Comparison of digital notch filters and a subtraction procedure for power-line interference removal.
• Implementation of adaptive synchronized sampling to manage frequency modulations.
• Development of a software-based measurement for power-line interference period, suitable for battery-operated devices.

Main Results:

• Digital notch filters were found to unacceptably affect QRS complexes in ECG signals.
• The subtraction procedure effectively eliminated interferences with variable amplitude and frequency.
• Adaptive synchronized sampling successfully overcame frequency modulations.

Conclusions:

• The subtraction procedure is superior to digital notch filters for power-line interference cancellation in ECG, preserving signal quality.
• Adaptive synchronized sampling, particularly with software-based period measurement, offers a versatile solution for ECG interference removal.
• This approach enhances the reliability of ECG analysis, especially in mobile or battery-powered applications.