Development of a wearable HRV telemetry system to be operated by non-experts in daily life

A telemetry system for the measurement of heart rate variability (HRV) with automatic gain control has been developed with a low-cost manufacturing process and a low-power consumption design. The proposed automatic gain control technique provided highly reliable RR interval (RRI) detection for subjects of different ages, and enabled the subjects to use the system without any expert knowledge of the electrocardiogram (ECG) measurement. All the components and functions for the RRI measurement were implemented on a wearable telemeter which can operate for up to 440 h with a CR2032 coin battery, and the wirelessly transmitted RRI data is stored into a PC by a receiver via a USB connection. The errors of the RRI detection occurred at less than 2% probability in subjects of five different ages. In a long-term measurement of a young subject that extended over 48 h, the results showed a 0.752% probability of recurring errors. The obtained results suggest that the proposed system enables the long-term monitoring of HRV for both clinical care and healthcare operated by a non-expert.