Elimination of AC interference in electrocardiogram using IIR notch filter with transient suppression

Area of Science:

• Biomedical Engineering
• Signal Processing

Background:

• Power line (AC) interference significantly degrades the quality of electrocardiogram (ECG) recordings.
• Conventional Infinite Impulse Response (IIR) notch filters often suffer from undesirable transient states when eliminating AC interference.
• Arbitrary initial conditions in conventional filters can lead to suboptimal performance in transient suppression.

Purpose of the Study:

• To investigate a novel technique for suppressing transient states in IIR notch filters.
• To improve the effectiveness of notch filters in removing power line interference from ECG signals.
• To enhance the initial performance of notch filters by optimizing initial values.

Main Methods:

• The proposed technique utilizes vector projection to determine optimal initial values for IIR notch filters.
• This method is applied to notch and comb filters designed for eliminating AC interference in ECG data.
• Performance comparison is conducted between the proposed technique and conventional notch filters with arbitrary initial conditions.

Main Results:

• The investigated technique demonstrates superior transient suppression compared to conventional notch filters.
• Improved performance in eliminating power line interference during ECG recording was observed.
• The enhanced performance comes with a slight increase in computational load at the filter's initiation.

Conclusions:

• Vector projection offers an effective method for initializing IIR notch filters to suppress transient states.
• This technique significantly improves the filtering of AC interference in ECG signals.
• The trade-off of increased initial computation is justified by the enhanced filtering accuracy.