Code Division Multi-Point RF Near-Field Cardiac Sensing System for Noninvasive Atrioventricular and Interventricular Dyssynchrony Detection

Monitoring cardiac mechanical dyssynchrony of a patient has a pivotal role in the cardiovascular disease and cardiac resynchronization therapy (CRT), however current approaches highly demand on the operator's skill and experience. In addition, the clinical instrument is limited by high standard operation conditions and hardware and maintenance costs, which leads to restricted deployment in daily life monitoring. To solve the problems, we propose a code division multi-point near-field cardiac RF sensing system that the mechanical movements of the heart chambers can be directly modulated to the radio frequency signal, from which the signals obtained through processing and analysis can not only locate the P-wave, QRS-waves, and T-wave in the electrocardiogram (ECG), but also they are used to analyze atrioventricular mechanical dyssynchrony and interventricular mechanical dyssynchrony. Furthermore, to reduce the crosstalk between signals from different channels and improve digital signal dynamic range, code division is applied for the multiple sensing points access. The RF sensing system can be readily designed with a high sampling rate, 50 kSps in this work, to recover the high frequency mechanical dynamics of the heart. The system demonstrated in this work provides 4-channel cardiac monitoring on the heart chambers with a high dynamic range, temporal resolution of 20 µs, and frequency response of 25 kHz. This novel method of monitoring the mechanical movement of the heartbeat provides a new candidate to further explore the cardiovascular disease and CRT treatment.