Introduction: Electrocardiography (ECG) patches are widely used for the remote monitoring of patients with chronic cardiac conditions. While ECG captures the heart's electrical activity, seismocardiography (SCG) provides insights into its mechanical function. To enable comprehensive remote monitoring of cardiac electromechanical activity, we have developed a wearable system that combines ECG and SCG in a single patch.
Methods: The system consists of a small, lightweight and wearable sensor embedded in a medical patch positioned on the sternum. The sensor integrates a 3-axis accelerometer for SCG, a single-lead ECG, and a microcontroller. The patch includes ECG electrodes that interface with the sensor when attached. Communication with a smartphone application is established via Bluetooth Low Energy (BLE). The app schedules and controls recordings, and transmits the collected data to a secure cloud database.
Measurements are configures for durations up to 27 seconds at a sampling rate of 250 Hz for ECG and 500 Hz for SCG. If the connection to the sensor fails, the system retries every 5 minutes until a successful recording is obtained. The only operational requirements are that the subject keeps a smartphone with the monitoring app nearby and maintains mobile internet connectivity.
Results: Device testing confirmed reliable acquisition of 27-second ECG and SCG recordings every 30 minutes over a period of 30 days without requiring a battery recharge or replacement. In a pilot test involving 3 subjects over a 48-hour period, configured for 30-minute recording intervals, a total of 255 recordings were obtained out of the expected 288 (96 recordings × 3 subjects), corresponding to 88.5% recording coverage.
Conclusion: The system enables long-term, remote, and continuous monitoring of cardiac electromechanical function using a combined ECG and SCG patch.