摘要
An individua ?s respiration and heart rates can be monitored in a contactless manner via Doppler radar. However, previous studies have failed to analyse cardiac activity based on the velocity of myocardial motion. In this study, a linear frequency-modulated continuous wave (FMCW) radar sensor is applied to demonstrate radiofrequency Doppler echocardiograms (RFDEs). An energy-focusing algorithm is proposed to finely select the target range bin. A high signal-to-noise rate signal is achieved and accurate Doppler cardiograms (DCGs) are obtained. The changes in the RFDEs are interpreted and labelled on the corresponding cardiac cycles in the electrocardiogram. In addition, data from different respiratory depths were collected and analysed. Several individuals were monitored over three consecutive days to validate the stability of the RFDE. The results suggest that RFDE can represent the heart cycle and may serve as auxiliary diagnostic tool for identifying cardiac systolic and diastolic defects.
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单位中山大学; 南方医科大学