Long-Term Continuous Ambulatory ECG Monitor with Beat-to-Beat Heart Rate Measurement in Real Time using ESP32

Abstract

This work presents a long-term continuous ambulatory ECG monitor for simultaneous acquisition and storage of leads DI, aVF, and V2, and beat-to-beat R wave detection using wavelet transform for heart rate measurement in real-time. The monitor has as its core the low-power ADS1294 analogue front-end of 4 channels, 24-bit analog-to-digital converters and programmable gain amplifiers, the low-power dual-core ESP32 microcontroller, a 32 GB micro SD memory for data storage and a 1.4 in thin-film transistor liquid crystal display (LCD) variant with a resolution of 128 x 128 pixels. The monitor has sampling rates of 1000 Hz, 500 Hz, and 250 Hz, bandwidth from 0 Hz to half the selected sampling rate, a CMRR of –115 dB, a resolution of 286 nV, a current consumption of 50 mA for an average battery life of 84 h, a lead-off detection and a real-time beat-to-beat heart rate measurement.