Implantable Fiber Bragg Grating Sensor for Continuous Heart Activity Monitoring: Ex-Vivo and In-Vivo Validation

Continuous and reliable cardiac function monitoring could improve medication adherence in patients at risk of heart failure. This work presents an innovative implantable Fiber Bragg Grating-based soft sensor designed to sense mechanical cardiac activity. The sensor was tested in an isolated beating ovine heart platform, with 3 different hearts operated in wide-ranging conditions. In order to investigate the sensor capability to track the ventricular beats in real-time, two causal algorithms were proposed for detecting the beats from sensor data and to discriminate artifacts. The first based on dynamic thresholds while the second is a hybrid convolutional and recurrent Neural Network. An error of 2.7 +/- 0.7 beats per minute was achieved in tracking the heart rate. Finally, we have confirmed the sensor reliability in monitoring the heart activity of healthy adult minipig with an error systematically lower than 1 Bpm.

Automated summary

An innovative implantable Fiber Bragg Grating-based soft sensor was designed to sense mechanical cardiac activity, providing continuous and reliable cardiac function monitoring. The sensor's capability to track ventricular beats in real-time was confirmed through testing on animal hearts, with errors consistently lower than 1 Bpm. The study also proposed two causal algorithms for detecting beats and discriminating artifacts from sensor data, achieving an error of 2.7 +/- 0.7 beats per minute in tracking heart rate.