Contactless Capacitive Electrocardiography Using Hybrid Flexible Printed Electrodes.

Glenn Cowan,Joshua Weeks,Mathieu Lessard-Tremblay,Laura Morelli,Ricardo J Zednik,Ghyslain Gagnon

doi:10.3390/s20185156

Abstract

Traditional capacitive electrocardiogram (cECG) electrodes suffer from limited patient comfort, difficulty of disinfection and low signal-to-noise ratio in addition to the challenge of integrating them in wearables. A novel hybrid flexible cECG electrode was developed that offers high versatility in the integration method, is well suited for large-scale manufacturing, is easy to disinfect in clinical settings and exhibits better performance over a comparable rigid contactless electrode. The novel flexible electrode meets the frequency requirement for clinically important QRS complex detection (0.67–5 Hz) and its performance is improved over rigid contactless electrode across all measured metrics as it maintains lower cut-off frequency, higher source capacitance and higher pass-band gain when characterized over a wide spectrum of patient morphologies. The results presented in this article suggest that the novel flexible electrode could be used in a medical device for cECG acquisition and medical diagnosis. The novel design proves also to be less sensitive to motion than a reference rigid electrode. We therefore anticipate it can represent an important step towards improving the repeatability of cECG methods while requiring less post-processing. This would help making cECG a viable method for remote cardiac health monitoring.

Highlights

Traditional electrocardiographic (ECG) measurement systems that rely on contact electrodes present challenges whenECG monitoring is required immediately, unobtrusively and frequently
Capacitive ECG technology is a potential alternative to the century-old traditional contact-based ECG technology and promises to revolutionize many aspects of ECG acquisition in both home and professional healthcare environments. cECG eliminates the need for trained professionals to perform the ECG acquisition on patients by being able to operate through clothing and on unprepared skin. cECG acquisition through clothing does not cause skin irritation and does not have an application time limit, facilitating long-term, continuous monitoring
We address the need for a capacitive cECG sensor that is flexible, efficient and easy to integrate in various devices

Summary

Introduction

Traditional electrocardiographic (ECG) measurement systems that rely on contact electrodes (electrodes which form a galvanic/ohmic connection with the patient’s body) present challenges whenECG monitoring is required immediately, unobtrusively and frequently. Traditional adhesive contact electrodes require placement by a trained healthcare provider on a clean, prepared skin surface to ensure accurate location (and morphology) and signal quality [1]. Limitations of standard wet gel contact electrode placement include placing them on the body correctly and removing them within their time limit to avoid skin reactions [2]. Capacitive ECG (cECG) technology is a potential alternative to the century-old traditional contact-based ECG technology and promises to revolutionize many aspects of ECG acquisition in both home and professional healthcare environments. CECG eliminates the need for trained professionals to perform the ECG acquisition on patients by being able to operate through clothing and on unprepared skin. CECG acquisition through clothing does not cause skin irritation and does not have an application time limit, facilitating long-term, continuous monitoring. Typical source capacitances can be on the order of 1–100 pF, producing source impedances of up to approximately

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