Lightweight Pause Detector-Based ECG Sensing Device for Intelligent Cardiac Health Monitoring

Sick sinus syndrome and heart blocks are types of heart rhythm disorders (arrhythmia) that are characterized by anirregular rhythm associated with pauses in the electrocardiogram (ECG) signal. The pauses in the ECG signal indicate a delay or complete interruption of electrical impulses from the atria to the ventricles, associated with life-threatening cardiac arrhythmias, with the severity and specific ECG patterns. Therefore, in this letter, we propose a lightweight automatic pause detector-based ECG sensing device by considering the resource constraints of affordable wearable cardiac health monitoring devices. The proposed pause detector consists of preprocessing, bipolar sequence addition, zero-crossing rate, and a decision rule that is integrated with a resource-constrained ECG computing platform. The proposed system achieved a sensitivity of 100% and a specificity of 99.75% across a wide variety of ECG morphologies, including local interval segments and beat-to-beat intervals. Further, evaluation results demonstrated that the pause detector can reduce the false R-peak detection rate by 86.06%-96.19%, leading to reliable R-peak detection without a search-back algorithm. On the Arduino Due (ARM Cortex-M3 CPU, 84 MHz clock, 96 kB SRAM, 512 kB flash) platform, interfacing with the ECG sensor, Bluetooth, and a Smartphone, it consumes energy of 58.85 mJ with a latency of 121 ms for processing a 9 s ECG signal. The proposed pause detector can be integrated with a resource-constrained ECG sensing device to detect the sinus node dysfunctions and heart blocks, and also improves the accuracy and reliability of R-peak detectors.