Capacitive driven-right-leg grounding in Indirect-contact ECG measurement

Area of Science:

• Biomedical Engineering
• Medical Instrumentation
• Signal Processing

Background:

• Indirect-contact electrocardiogram (IC-ECG) offers unconstrained, long-term monitoring but suffers from significant 60 Hz power line noise.
• This noise interference restricts the practical application and reliability of IC-ECG technology in home healthcare settings.
• Conventional direct-contact ECG systems utilize driven-right-leg grounding to mitigate noise, a technique not yet optimized for IC-ECG.

Purpose of the Study:

• To adapt and evaluate the driven-right-leg grounding technique for reducing common-mode noise in IC-ECG measurements.
• To overcome the limitation of high 60 Hz noise interference in unconstrained, long-term ECG monitoring systems.
• To enhance the signal quality and diagnostic accuracy of IC-ECG for potential home-use applications.

Main Methods:

• Implemented a driven-right-leg grounding system adapted for IC-ECG measurement setups.
• Utilized feedback of amplified common-mode noise inversion applied to the body via conductive chair seat textile.
• Measured the reduction in 60 Hz power line noise levels with the integrated driven-right-leg system.

Main Results:

• The adapted driven-right-leg grounding method significantly reduced the 60 Hz power line noise level in IC-ECG.
• A noise reduction of approximately -40 dB was achieved with a driven-right-leg gain of 1000.
• Demonstrated the effectiveness of active noise cancellation for improving IC-ECG signal integrity.

Conclusions:

• The driven-right-leg grounding method is a viable and effective solution for mitigating power line noise in IC-ECG.
• This technique enhances the feasibility of long-term, unconstrained ECG monitoring for remote and home healthcare.
• Further development could lead to more robust and reliable IC-ECG devices for widespread clinical and personal use.