Contact-free piezo electric sensor used for real-time analysis of inter beat interval series

In heart rate monitoring, the Electrocardiogram (ECG) is commonly used and is considered to be the gold standard in the field. However, long term monitoring with ECG is rarely used except for ICU and 24-hours Holter. Prolonged cardiac monitoring in various setups can be achieved using a Ballistocardiogram (BCG), which serves as a convenient way for contact free monitoring of the heart activity. This study was aimed to assess the potential of measuring cardiac Inter Beat Interval (IBI) series in real-time using a BCG signal using a contact-free piezo-electric sensor placed under the mattress (EarlySense Ltd.). In this paper, we evaluated three real-time novel algorithm that provide IBI measurement, predicated IBI measurement accuracy and IBI statistic. The performance of these algorithms was evaluated using IBI series derived from one-lead ECG signal. The results support the claim that under the mattress piezoelectric sensor can be used to accurately measure IBI in real-time, and establish the basis for Heart Rate Variability (HRV) analysis.