Heart Rate And Heart Rate Variability Indexes Estimated By Mechanical Signals From A Skin-Interfaced IMU

Heart rate (HR) and heart rate variability (HRV) indexes are useful parameters for diagnosis and prevention of several cardiovascular disease. Typically, these parameters are estimated from electrocardiogram (ECG) waveforms. However, many methods based on cardio-mechanical signals associated with heart beating are under investigation. The use of these methods has been boosted by the recent developments in sensors' fabrication and post-processing algorithms. Wearable sensors can be used to register these vibrations in form of changes of superficial accelerations and chest wall angular velocities. In this paper, we investigated the performance of a single skin-interfaced Inertial Measurement Unit (IMU) to estimate HR and HRV in the time and frequency domains. The analysis was performed in two different postures (i.e., supine and seated) to assess the influence of this condition on the performance of the proposed method and using accelerometer and gyroscope signals separately. Five volunteers were recruited in this feasibility study. Results show promising performances of the IMU in estimating HR and HRV especially when the accelerometer signals are used in seated posture.