Implementation and Analysis of Wireless ECG Signal Conditioning Circuit for Smart Healthcare Solution

Heart activity monitoring is essential in the identification and classification of different heart diseases. This can be performed using wearable electrocardiography where biosignals acquired will have low amplitude and also subjected to several noises such as baseline wandering, motion artefacts and powerline interference. In this study, wearable ECG Monitoring system (EMS) have been developed using instrumentation amplifier AD620 with a right leg driven circuit and 50 Hz notch filter. For this, signal acquisition is performed by placing two sets of electrodes on left arm, right arm and right leg. Then signals are recorded using EMS and AD8232 device. The recorded signals are amplified and filtered using signal conditioning circuits present in EMS. Further, these pre-processed signals are converted from analog to digital form using Arduino UNO. The capability of EMS to record ECG signal is validated by comparing the recorded signals with AD8232 simultaneously. The obtained signal is interpreted using correlation analysis and Bland-Altmann plot. Results indicate that the peaks in the ECG signal obtained from AD8232 and EMS are visually overlapping and characteristics of ECG intervals have high similarity. It is also noted that EMS is able to reduce the 50Hz noise effectively when compared to AD8232. The correlation coefficient is seen to be concentrated in the range of 0.8 representing strong similarity between two measurement devices. The Bland-Altman plot shows mean bias ± standard deviation between AD8232 and EMS is $0.07 \pm 0.17$ indicating that the data obtained from the EMS and AD8232 have good similarity. Thus, the proposed circuit can be utilized for wireless, portable and wearable technology applications.