Fully integrated flexible long-term electrocardiogram recording patch with gel-less adhesive electrodes for arrhythmia detection

A mechanically flexible and fully integrated electrocardiogram (ECG) recording patch (ERP) that simultaneously monitors the ECG signals and detects the arrhythmia is presented. A simplified two-step process is applied to fabricate the acetylene carbon black (AB)/ polydimethylsiloxane (PDMS) electrodes. The soft and adhesive nature of polymer composite electrodes allows conformal contact to the skin. The ERP integrates ECG front end circuits, microcontroller chip and wireless communication unit on a flexible printed circuit boards (FPCB) with electrodes attached on its back, which bridges the technological gap among the signal acquisition, processing, and wireless transmission in the wearable electronics. The ERP can be deformed easily under stretching and bending actions by a special connection of two squares through serpentine traces. With the concentration of 7 wt% AB, the average signal-to-noise ratio (SNR) of the built electrodes at different postures (sit, stand and walk) during electrocardiography are assessed as 17.4 dB, 16.1 dB and 5.6 dB, respectively. Similarly, the SNR of the ERP with Ag/AgCl electrodes are 22.1 dB, 20.6 dB and 10.3 dB, respectively. The performance of the AB/PDMS electrodes are very close to the standard Ag/AgCl electrodes. In addition, the ERP have the ability of anti-interference from environmental noise and motion artifacts (MA). Benefited from implemented microcontroller unit (MCU) platform, the ERP allows sophisticated signal processing with the introduction of discrete wavelet transform (DWT) and support vector machine (SVM) algorithms, which achieves high classification accuracy of 98.7% for online arrhythmia detection. The designed platform provides a wide range of applications for other personalized physiological monitoring and diagnosis.