Qualitative and quantitative evaluation of a new wearable device for ECG and respiratory Holter monitoring

Methods

Thirty cardiorespiratory patients and ten healthy subjects were studied for 24 h during their usual life activities. In 8 healthy subjects, simultaneous measurements of the device and of an ergo-spirometer were performed during different levels of ventilation in five different body positions. The quality of ECG signals in terms of measurability of heart rate, P wave, QRS complex and ST segment, was analyzed by four expert cardiologists/respiratory physiologists using an arbitrary 1–5 scale.

The sum of the respiratory signals was used to calculate the respiratory rate, inspiratory time and relative changes of tidal volume. These parameters were compared to ergo-spirometer measurements. Results: Median quality value was >3 for heart rate, QRS complex, ST segment and P wave (except in L3, aVL, aVF, V1 and V2 leads).

Median quality of respiratory traces was >4 in patients and between 3 and 4 in healthy subjects. The respiratory monitoring of respiratory rate and inspiratory time was accurate in all body positions. Tidal volumes were underestimated due to a high level of ventilation.

Conclusions: The L.I.F.E. device provides an accurate continuous monitoring of cardiorespiratory signals during the 24 h both in normal subjects and cardiorespiratory patients.