Doppler Cardiogram: A Remote Detection of Human Heart Activities

Most medical instruments invented to measure human heart activities, such as electrocardiograms (ECGs), rely on contact electrodes. This causes discomfort and limits application scenarios. Remote acquisition of μV-level bioelectrical cardiac signals through ECG measurement is theoretically challenging. Based on the analysis of magnetic resonance imaging to the volume change of human hearts, we found that a single radar sensor can be used to remotely detect a Doppler cardiogram (DCG) at a distance up to 1 m, by retrieving Doppler signals induced by combined atrial and ventricular motions conducted to the skin of the back chest. This DCG can provide all the timing information of the P-wave, QRS-waves, and T-wave carried in ECGs. The implemented miniature remote sensor could be an ideal portable instrument for patients, such as burn victims, extending application scenarios to personal healthcare, battlefield rescue, and others.