Monitoring Cardiac Electromechanical Activity Underwater Using Micro Electro Mechanical Systems

The increasing prevalence of scuba diving in both physically active and sedentary individuals underscores the need for technology enabling real-time cardiovascular monitoring during underwater activities. This study aimed to assess cardiac electro-mechanical activity and its adaptation underwater in controlled dives. ECG and seismocardiographic (SCG) signals were collected from 23 experienced divers using the EcgMove4 Movisens device, worn with adhesive disposable electrodes under a dry suit. The protocol included four phases: baseline, underwater at two and five meters depth, and post-dive. Heart rate (HR) and HR variability analysis (HRV) was performed on the ECG, and both ECG and SCG signals were used to assess respiratory frequency. Fiducial points for isovolumetric contraction and aortic valve opening were extracted on the SCG, from which morphological SCG biomarkers were computed. Finally, beats integral of linear and rotational kinetic energies were calculated. Respiratory frequency decreased underwater, with sympathetic and parasympathetic activation. Initial increases in SCG parameters and kinetic energy were observed, followed by gradual physiological adaptation. These findings suggest SCG efficacy to detect myocardial mechanical activity underwater, complementing ECG for comprehensive cardiovascular monitoring using wearable devices, highlighting promising avenues for future research in underwater cardiovascular assessment and monitoring.