Evaluation of a newly designed shirt-based ECG and breathing sensor for home-based training as part of cardiac rehabilitation for coronary artery disease

Background Participation in phase-III cardiac rehabilitation (CR) remains low but adherence could potentially be improved with supervised home-based CR. New technological approaches are needed to provide sufficient supervision with respect to safety and performance of individual exercise programmes. Design The newly designed closed-loop tool, HeartCycle's guided exercise (GEX) system, will support professionals and patients during exercise-based CR. Patients wear a dedicated shirt with incorporated wireless sensors, and ECG, heart rate (HR), breathing frequency (BF), and activity are monitored during exercise. This information is streamed live to a mobile device (PDA) that processes these parameters. Methods A phase-I study was performed to evaluate feasibility, function, and reliability of this GEX device and compare it to conventional cardiac exercise testing (CPX, spiroergometry) in 50 patients (seven women, meanSD age 699 years, body mass index 26 +/- 3kg/m(2), ejection fraction 58 +/- 10%). ECG, HR, and BF were monitored using standard equipment and the GEX device simultaneously. Furthermore, HR recorded on the PDA was compared with CPX measurements. Results The fit of the shirt and the sensor was good. No technical problems were encountered. All occurring arrhythmia were reliably detected. There was an acceptable comparability between HR on the GEX device vs. CPX, a good comparability between HR on the PDA vs. CPX, and a moderate comparability between BF on the GEX device vs. CPX. Conclusions Comparability between CPX and the GEX device was acceptable for HR measurement and moderate for BF; arrhythmias were reliably detected. HR processing and display on the PDA was even better comparable. The whole system seems suitable for monitoring home-based CR. Further studies are now needed to implement training prescription to facilitate individual exercise.